Recent Advances in the Synthesis of Difluorinated Architectures from Trifluoromethyl Groups

Tuning the regioselective functionalization of trifluoromethylated dienes via lanthanum‐mediated single C‐F bond activation

(2021) Tarun Kumar et al.   CHEMISTRY-A EUROPEAN JOURNAL

Photoredox/Hydrogen Atom Transfer Cocatalyzed C–H Difluoroallylation of Amides, Ethers, and Alkyl Aldehydes

(2021) Yuan-Qiang Guo et al.   ORGANIC LETTERS

Sequential C–F bond functionalizations of trifluoroacetamides and acetates via spin-center shifts

(2021) You-Jie Yu et al.   SCIENCE

Site-Selective Defluorinative sp3 C–H Alkylation of Secondary Amides

(2021) Wen-Jun Yue et al.   JOURNAL OF THE AMERICAN CHEMICAL SOCIETY

Remote Regioselective Radical C–H Functionalization of Unactivated C–H Bonds in Amides: The Synthesis of gem-Difluoroalkenes

(2021) Qu-Ping Hu et al.   ORGANIC LETTERS

Selective C–F Bond Allylation of Trifluoromethylalkenes

(2021) Chuan Zhu et al.   ANGEWANDTE CHEMIE-INTERNATIONAL EDITION

Chromium-Catalyzed Allylic Defluorinative Ketyl Olefin Coupling

(2021) Chang Zhang et al.   JOURNAL OF THE AMERICAN CHEMICAL SOCIETY

Visible-Light-Induced Palladium-Catalyzed Selective Defluoroarylation of Trifluoromethylarenes with Arylboronic Acids

(2021) Yun-Cheng Luo et al.   JOURNAL OF THE AMERICAN CHEMICAL SOCIETY

Photoredox Generation of N-Centered Hydrazonyl Radicals Enables the Construction of Dihydropyrazole-Fused gem-Difluoroalkenes

(2021) Qi-Sheng Gao et al.   ORGANIC LETTERS

Visible-Light-Mediated C–I Difluoroallylation with an α-Aminoalkyl Radical as a Mediator

(2021) Fuyang Yue et al.   ORGANIC LETTERS

NiH-Catalyzed Migratory Defluorinative Olefin Cross-Coupling: Trifluoromethyl-Substituted Alkenes as Acceptor Olefins to Form gem -Difluoroalkenes

(2020) Fenglin Chen et al.   ANGEWANDTE CHEMIE-INTERNATIONAL EDITION

Defluoroalkylation of sp3 C–F Bonds of Industrially Relevant Hydrofluoroolefins

(2020) Nicholas Phillips et al.   CHEMISTRY-A EUROPEAN JOURNAL

Frustrated Lewis-Pair-Meditated Selective Single Fluoride Substitution in Trifluoromethyl Groups

(2020) Dipendu Mandal et al.   JOURNAL OF THE AMERICAN CHEMICAL SOCIETY

Catalyzing the Hydrodefluorination of CF3-Substituted Alkenes by PhSiH3. H• Transfer from a Nickel Hydride

(2020) Chengbo Yao et al.   JOURNAL OF THE AMERICAN CHEMICAL SOCIETY

Synthesis of Ring-Fluorinated Thiophene Derivatives Based on Single C–F Bond Activation of CF3-Cyclopropanes: Sulfanylation and 5-endo-trig Cyclization

(2020) Kohei Fuchibe et al.   ORGANIC LETTERS

Visible-Light-Mediated β-C–H gem-Difluoroallylation of Aldehydes and Cyclic Ketones through C–F Bond Cleavage of 1-Trifluoromethyl Alkenes

(2020) Devireddy Anand et al.   ORGANIC LETTERS

Visible-Light-Induced Deoxygenation/Defluorination Protocol for Synthesis of γ,γ-Difluoroallylic Ketones

(2020) Yuan-Qiang Guo et al.   ORGANIC LETTERS

Visible‐Light‐Induced Radical Defluoroborylation of Trifluoromethyl Alkenes: An Access to gem‐Difluoroallylboranes

(2020) Guojun Chen et al.   ADVANCED SYNTHESIS & CATALYSIS

Synthesis of Diverse Aromatic Ketones through C–F Cleavage of Trifluoromethyl Group

(2020) Mai Ikeda et al.   CHEMISTRY-A EUROPEAN JOURNAL

Recent Advances in Transition Metal‐Catalyzed Functionalization of gem ‐Difluoroalkenes

(2020) Suvajit Koley et al.   ISRAEL JOURNAL OF CHEMISTRY

Umpolung Difunctionalization of Carbonyls via Visible-Light Photoredox Catalytic Radical-Carbanion Relay

(2020) Shun Wang et al.   JOURNAL OF THE AMERICAN CHEMICAL SOCIETY

Organophotoredox Hydrodefluorination of Trifluoromethylarenes with Translational Applicability to Drug Discovery

(2020) Jeroen B. I. Sap et al.   JOURNAL OF THE AMERICAN CHEMICAL SOCIETY

Titanocene-Catalyzed Reductive Domino Epoxide Ring Opening/Defluorinative Cross-Coupling Reaction

(2020) Zhiyang Lin et al.   ORGANIC LETTERS

Merger of C–F and C–N Bond Cleavage in Cross-Electrophile Coupling for the Synthesis of gem-Difluoroalkenes

(2020) Youxiang Jin et al.   ORGANIC LETTERS

Cobalt- or copper-catalyzed synthesis of gem-difluoroallyl MIDA boronates from α-trifluoromethyl alkenes

(2020) Yisen Liu et al.   TETRAHEDRON LETTERS

Photocatalytic radical defluoroalkylation of unactivated alkenes via distal heteroaryl ipso-migration

(2020) Xin Yuan et al.   Communications Chemistry

Defluorinative Functionalization of Pd(II) Fluoroalkyl Complexes

(2020) Michael M. Wade Wolfe et al.   JOURNAL OF THE AMERICAN CHEMICAL SOCIETY

Access to gem-Difluoro Olefins via C–H Functionalization and Dual Role of Anilines

(2020) Zhen Yang et al.   ORGANIC LETTERS

Organo-photoredox catalyzed defluoroacetalation of α-trifluoromethyl alkenes for synthesis of masked γ,γ-difluoroallylic aldehydes

(2020) Pan Xiang et al.   TETRAHEDRON LETTERS

The coupling of alkylboronic acids with α-(trifluoromethyl)styrenes by Lewis base/photoredox dual catalysis

(2020) Yuefeng Chen et al.   TETRAHEDRON LETTERS

Migratory functionalization of unactivated alkyl bromides for construction of all-carbon quaternary centers via transposed tert-C-radicals

(2020) Chuan Zhu et al.   Nature Communications

Manganese-mediated reductive functionalization of activated aliphatic acids and primary amines

(2020) Zhan Li et al.   Nature Communications

Visible-Light-Driven Catalytic Reductive Carboxylation with CO2

(2020) Zhen Zhang et al.   ACS Catalysis

Electroreductive Olefin–Ketone Coupling

(2020) Pengfei Hu et al.   JOURNAL OF THE AMERICAN CHEMICAL SOCIETY

Synthesis of gem-Difluoroalkenes via Zn-Mediated Decarboxylative/Defluorinative Cross-Coupling

(2020) Hai-Wu Du et al.   ORGANIC LETTERS

Two C(sp3)–F Bond Activation in a CF3 Group: ipso-Defluorinative Amination Triggered 1,3-Diamination of (Trifluoromethyl)alkenes with Indoles, Carbazoles, Pyrroles, and Sulfonamides

(2020) Hao Zeng et al.   ORGANIC LETTERS

Ni-Catalyzed Defluorination for the Synthesis of gem-Difluoro-1,3-dienes and Their [4 + 2] Cycloaddition Reaction

(2019) Minqi Zhou et al.   ORGANIC LETTERS

Photoredox Defluorinative Alkylation of 1‐Trifluoromethyl Alkenes and 1,3‐Butadienes with 1,4‐Dihydropyridines as Alkylation Reagents

(2019) Haoguo Chen et al.   Asian Journal of Organic Chemistry

Synthesis of gem-Difluoroalkenes by Merging Ni-Catalyzed C–F and C–C Bond Activation in Cross-Electrophile Coupling

(2019) Decai Ding et al.   ORGANIC LETTERS

Single C(sp3)–F Bond Activation in a CF3 Group: Ipso-Defluorooxylation of (Trifluoromethyl)alkenes with Oximes

(2019) Hao Zeng et al.   ORGANIC LETTERS

Open-Air Alkylation Reactions in Photoredox-Catalyzed DNA-Encoded Library Synthesis

(2019) James P. Phelan et al.   JOURNAL OF THE AMERICAN CHEMICAL SOCIETY

Visible-Light-Promoted Redox Neutral γ,γ-Difluoroallylation of Cycloketone Oxime Ethers with Trifluoromethyl Alkenes via C–C and C–F Bond Cleavage

(2019) Yuwei He et al.   ORGANIC LETTERS

Defluorinative C(sp 3 )−P Bond Construction for the Synthesis of Phosphorylation gem ‐Difluoroalkenes under Catalyst‐ and Oxidant‐Free Conditions

(2019) Congyu Li et al.   Chemistry-An Asian Journal

Copper-Catalyzed Carboxylation of C–F Bonds with CO2

(2019) Si-Shun Yan et al.   ACS Catalysis

Transition‐Metal‐Free Defluorosilylation of Fluoroalkenes with Silylboronates

(2019) Pan Gao et al.   CHINESE JOURNAL OF CHEMISTRY

Selective Defluoroallylation of Trifluoromethylarenes

(2019) Chaosheng Luo et al.   JOURNAL OF THE AMERICAN CHEMICAL SOCIETY

Selective C–F Functionalization of Unactivated Trifluoromethylarenes

(2019) David B. Vogt et al.   JOURNAL OF THE AMERICAN CHEMICAL SOCIETY

Opportunities and Challenges for Catalysis in Carbon Dioxide Utilization

(2019) Michael D. Burkart et al.   ACS Catalysis

Reductive Allylic Defluorinative Cross-Coupling Enabled by Ni/Ti Cooperative Catalysis

(2019) Zhiyang Lin et al.   ORGANIC LETTERS

Synthesis of gem -Difluoro Olefins through C−H Functionalization and β-fluoride Elimination Reactions

(2019) Zhen Yang et al.   ANGEWANDTE CHEMIE-INTERNATIONAL EDITION

Catalytic Enantioselective Boryl and Silyl Substitution with Trifluoromethyl Alkenes: Scope, Utility, and Mechanistic Nuances of Cu–F β-Elimination

(2019) Paulo H. S. Paioti et al.   JOURNAL OF THE AMERICAN CHEMICAL SOCIETY

Coupling of Trifluoroacetaldehyde N-Triftosylhydrazone with Organoboronic Acids for the Synthesis of gem-Difluoroalkenes

(2019) Yu Ma et al.   ORGANIC LETTERS

A Copper(I)-Catalyzed Enantioselective γ-Boryl Substitution of Trifluoromethyl-Substituted Alkenes: Synthesis of Enantioenriched γ,γ-gem -Difluoroallylboronates

(2018) Ryoto Kojima et al.   ANGEWANDTE CHEMIE-INTERNATIONAL EDITION

Transition metal-catalyzed carboxylation reactions with carbon dioxide

(2018) Ruben Martin et al.   ANGEWANDTE CHEMIE-INTERNATIONAL EDITION

Transition Metal-Mediated and -Catalyzed C-F Bond Activation via Fluorine Elimination

(2018) Takeshi Fujita et al.   ANGEWANDTE CHEMIE-INTERNATIONAL EDITION

Picking one out of three: selective single C-F activation in trifluoromethyl groups

(2018) Florian Jaroschik   CHEMISTRY-A EUROPEAN JOURNAL

Recent Progress on Difluoromethylation Methods

(2018) Weiqiang Wang et al.   CHINESE JOURNAL OF ORGANIC CHEMISTRY

Fluorine and Fluorinated Motifs in the Design and Application of Bioisosteres for Drug Design

(2018) Nicholas A. Meanwell   JOURNAL OF MEDICINAL CHEMISTRY

Enantioselective Copper-Catalyzed Defluoroalkylation Using Arylboronate-Activated Alkyl Grignard Reagents

(2018) Minyan Wang et al.   JOURNAL OF THE AMERICAN CHEMICAL SOCIETY

A Copper-Catalyzed Reductive Defluorination of β-Trifluoromethylated Enones via Oxidative Homocoupling of Grignard Reagents

(2018) Xiaoting Wu et al.   ORGANIC LETTERS

Direct C(sp 3 )−H difluoroallylation of diarylmethanes with α-(trifluoromethyl) styrenes at room temperature

(2018) Xinfei Ji et al.   TETRAHEDRON

Cu-Catalyzed tertiary alkylation of α-(trifluoromethyl)styrenes with tertiary alkylmagnesium reagents

(2018) Wenpeng Dai et al.   Organic Chemistry Frontiers

Transition-Metal (Cu, Pd, Ni)-Catalyzed Difluoroalkylation via Cross-Coupling with Difluoroalkyl Halides

(2018) Zhang Feng et al.   ACCOUNTS OF CHEMICAL RESEARCH

Visible Light-Mediated Trifluoromethylation of Fluorinated Alkenes via C−F Bond Cleavage

(2018) Liu-Hai Wu et al.   ADVANCED SYNTHESIS & CATALYSIS

Copper-Catalyzed Defluorinative Thioannulation of Trifluoropropynes for the Synthesis of 1,2-Dithiole-3-thiones

(2018) Feng Wei et al.   ADVANCED SYNTHESIS & CATALYSIS

Photoredox Catalysis as a Strategy for CO2 Incorporation: Direct Access to Carboxylic Acids from a Renewable Feedstock

(2018) Charles Yeung   ANGEWANDTE CHEMIE-INTERNATIONAL EDITION

Activation of C–F bonds α to C–C multiple bonds

(2018) Jean-Denys Hamel et al.   CHEMICAL COMMUNICATIONS

Synthesis of gem-Difluoroalkenes via Nickel-Catalyzed Allylic Defluorinative Reductive Cross-Coupling

(2018) Yun Lan et al.   ACS Catalysis

Copper-Catalyzed Asymmetric Defluoroborylation of 1-(Trifluoromethyl)Alkenes

(2018) Pan Gao et al.   Chem

Rhodium-Catalyzed Enantioselective Defluorinative α-Arylation of Secondary Amides

(2018) Young Jin Jang et al.   ANGEWANDTE CHEMIE-INTERNATIONAL EDITION

Single C−F Bond Activation of the CF 3 Group with a Lewis Acid: CF 3 ‐Cyclopropanes as Versatile 4,4‐Difluorohomoallylating Agents

(2018) Kohei Fuchibe et al.   CHEMISTRY-A EUROPEAN JOURNAL

Copper-catalyzed synthesis of gem-difluoroallylboronates from α-trifluoromethyl alkenes and B2pin2

(2018) Xianghu Zhao et al.   TETRAHEDRON LETTERS

Synthesis of gem-Difluoroalkenes via Nickel-Catalyzed Reductive C–F and C–O Bond Cleavage

(2018) Zhiyang Lin et al.   ACS Catalysis

Selective Late-Stage Hydrodefluorination of Trifluoromethylarenes: A Facile Access to Difluoromethylarenes

(2017) Socrates B. Munoz et al.   EUROPEAN JOURNAL OF ORGANIC CHEMISTRY

β-Selective Reductive Coupling of Alkenylpyridines with Aldehydes and Imines via Synergistic Lewis Acid/Photoredox Catalysis

(2017) Katarzyna N. Lee et al.   JOURNAL OF THE AMERICAN CHEMICAL SOCIETY

Catalytic Defluoroalkylation of Trifluoromethylaromatics with Unactivated Alkenes

(2017) Hengbin Wang et al.   JOURNAL OF THE AMERICAN CHEMICAL SOCIETY

Selective Single C(sp3)–F Bond Cleavage in Trifluoromethylarenes: Merging Visible-Light Catalysis with Lewis Acid Activation

(2017) Kang Chen et al.   JOURNAL OF THE AMERICAN CHEMICAL SOCIETY

Niobium(v)-catalyzed defluorinative triallylation of α,α,α-trifluorotoluene derivatives by triple C–F bond activation

(2017) Kodai Saito et al.   ORGANIC & BIOMOLECULAR CHEMISTRY

Synthesis of gem-Difluoroallylboronates via FeCl2-Catalyzed Boration/β-Fluorine Elimination of Trifluoromethyl Alkenes

(2017) Yang Liu et al.   ORGANIC LETTERS

Recent advances in the synthesis and CF functionalization of gem-difluoroalkenes

(2017) Xuxue Zhang et al.   TETRAHEDRON LETTERS

Metal-Catalyzed Direct Difluoromethylation Reactions

(2017) Jian Rong et al.   Asian Journal of Organic Chemistry

The merger of transition metal and photocatalysis

(2017) Jack Twilton et al.   Nature Reviews Chemistry

Controlled Fluoroalkylation Reactions by Visible-Light Photoredox Catalysis

(2016) Tanmay Chatterjee et al.   ACCOUNTS OF CHEMICAL RESEARCH

Fine Design of Photoredox Systems for Catalytic Fluoromethylation of Carbon–Carbon Multiple Bonds

(2016) Takashi Koike et al.   ACCOUNTS OF CHEMICAL RESEARCH

Mechanistic Perspectives on Organic Photoredox Catalysis for Aromatic Substitutions

(2016) Michal Majek et al.   ACCOUNTS OF CHEMICAL RESEARCH

Free Radical Chemistry Enabled by Visible Light-Induced Electron Transfer

(2016) Daryl Staveness et al.   ACCOUNTS OF CHEMICAL RESEARCH

Polarity-Reversed Allylations of Aldehydes, Ketones, and Imines Enabled by Hantzsch Ester in Photoredox Catalysis

(2016) Li Qi et al.   ANGEWANDTE CHEMIE-INTERNATIONAL EDITION

Single C−F Bond Cleavage of Trifluoromethylarenes with an ortho -Silyl Group

(2016) Suguru Yoshida et al.   ANGEWANDTE CHEMIE-INTERNATIONAL EDITION

Synthetic Strategies toward Natural Products Containing Contiguous Stereogenic Quaternary Carbon Atoms

(2016) Martin Büschleb et al.   ANGEWANDTE CHEMIE-INTERNATIONAL EDITION

Diboron(4) Compounds: From Structural Curiosity to Synthetic Workhorse

(2016) Emily C. Neeve et al.   CHEMICAL REVIEWS

Phosphonate Biochemistry

(2016) Geoff P. Horsman et al.   CHEMICAL REVIEWS

Organic Photoredox Catalysis

(2016) Nathan A. Romero et al.   CHEMICAL REVIEWS

Catalytic Enantioselective Desymmetrization Reactions to All-Carbon Quaternary Stereocenters

(2016) Xing-Ping Zeng et al.   CHEMICAL REVIEWS

Palladium-Catalyzed Transformations of Alkyl C–H Bonds

(2016) Jian He et al.   CHEMICAL REVIEWS

Formation of C(sp3 )-C(sp3 ) Bonds through Nickel-Catalyzed Decarboxylative Olefin Hydroalkylation Reactions

(2016) Xi Lu et al.   CHEMISTRY-A EUROPEAN JOURNAL

Photoredox Catalysis in Organic Chemistry

(2016) Megan H. Shaw et al.   JOURNAL OF ORGANIC CHEMISTRY

Catalytic activation of a single C–F bond in trifluoromethyl arenes

(2016) Hester Dang et al.   Chemical Science

Recent Advances in Transition-Metal-Catalyzed Synthetic Transformations of Organosilicon Reagents

(2016) Takeshi Komiyama et al.   ACS Catalysis

Recent advances in photoinduced trifluoromethylation and difluoroalkylation

(2016) Xiaolin Pan et al.   Organic Chemistry Frontiers

Nickel-Catalyzed Reductive Couplings

(2016) Xuan Wang et al.   Topics in Current Chemistry

Advances in Transition-Metal-Mediated Di-and Monofluoroalkylations

(2015) Chuanfa Ni et al.   ACTA CHIMICA SINICA

Transformation of Trifluorotoluenes Triggered by Titanium(IV) Chloride-Catalyzed Hydrodefluorination using Hydrosilanes

(2015) Takayuki Yamada et al.   ADVANCED SYNTHESIS & CATALYSIS

Use of Trifluoromethyl Groups for Catalytic Benzylation and Alkylation with Subsequent Hydrodefluorination

(2015) Jiangtao Zhu et al.   ANGEWANDTE CHEMIE-INTERNATIONAL EDITION

Carbon Trifluoromethylation Reactions of Hydrocarbon Derivatives and Heteroarenes

(2015) Concepción Alonso et al.   CHEMICAL REVIEWS

Boron-selective reactions as powerful tools for modular synthesis of diverse complex molecules

(2015) Liang Xu et al.   CHEMICAL SOCIETY REVIEWS

Applications of Fluorine in Medicinal Chemistry

(2015) Eric P. Gillis et al.   JOURNAL OF MEDICINAL CHEMISTRY

Using carbon dioxide as a building block in organic synthesis

(2015) Qiang Liu et al.   Nature Communications

Electrophilic Trifluoromethylation by Use of Hypervalent Iodine Reagents

(2014) Julie Charpentier et al.   CHEMICAL REVIEWS

Addition of CF3 across unsaturated moieties: a powerful functionalization tool

(2014) Estíbaliz Merino et al.   CHEMICAL SOCIETY REVIEWS

Reductive Cross-Coupling Reactions between Two Electrophiles

(2014) Christiane E. I. Knappke et al.   CHEMISTRY-A EUROPEAN JOURNAL

Cross-Electrophile Coupling: Principles of Reactivity and Selectivity

(2014) Daniel A. Everson et al.   JOURNAL OF ORGANIC CHEMISTRY

Recent advances in homogeneous nickel catalysis

(2014) Sarah Z. Tasker et al.   NATURE

Fluorine in Pharmaceutical Industry: Fluorine-Containing Drugs Introduced to the Market in the Last Decade (2001–2011)

(2013) Jiang Wang et al.   CHEMICAL REVIEWS

Visible Light Photoredox Catalysis with Transition Metal Complexes: Applications in Organic Synthesis

(2013) Christopher K. Prier et al.   CHEMICAL REVIEWS

Selection of boron reagents for Suzuki–Miyaura coupling

(2013) Alastair J. J. Lennox et al.   CHEMICAL SOCIETY REVIEWS

Catalytic Ketyl-Olefin Cyclizations Enabled by Proton-Coupled Electron Transfer

(2013) Kyle T. Tarantino et al.   JOURNAL OF THE AMERICAN CHEMICAL SOCIETY

Recent Applications of Organic Dyes as Photoredox Catalysts in Organic Synthesis

(2013) David A. Nicewicz et al.   ACS Catalysis

CH Bond Functionalization: Emerging Synthetic Tools for Natural Products and Pharmaceuticals

(2012) Junichiro Yamaguchi et al.   ANGEWANDTE CHEMIE-INTERNATIONAL EDITION

Aggregation induced emission (AIE) of trifluoromethyl substituted distyrylbenzenes

(2012) Zhengwei Shi et al.   CHEMICAL COMMUNICATIONS

Cross-Coupling Reactions Of Organoboranes: An Easy Way To Construct CC Bonds (Nobel Lecture)

(2011) Akira Suzuki   ANGEWANDTE CHEMIE-INTERNATIONAL EDITION

Exploring the Boundaries of Additivity: Mixtures of NADH:Quinone Oxidoreductase Inhibitors

(2011) Jonathan Boyd et al.   CHEMICAL RESEARCH IN TOXICOLOGY

Synthesis and Metal-Catalyzed Reactions of gem-Dihalovinyl Systems

(2011) Giorgio Chelucci   CHEMICAL REVIEWS

Synopsis of Some Recent Tactical Application of Bioisosteres in Drug Design

(2011) Nicholas A. Meanwell   JOURNAL OF MEDICINAL CHEMISTRY

Samarium Diiodide Mediated Reactions in Total Synthesis

(2009) K. C. Nicolaou et al.   ANGEWANDTE CHEMIE-INTERNATIONAL EDITION

C−F Bond Activation in Organic Synthesis

(2009) Hideki Amii et al.   CHEMICAL REVIEWS

The Many Roles for Fluorine in Medicinal Chemistry

(2008) William K. Hagmann   JOURNAL OF MEDICINAL CHEMISTRY

Pentadienyl Complexes of Alkali Metals: Structure and Bonding†

(2008) Erick Cerpa et al.   ORGANOMETALLICS

Glyphosate: a once-in-a-century herbicide

(2008) Stephen O Duke et al.   PEST MANAGEMENT SCIENCE

Understanding organofluorine chemistry. An introduction to the C–F bond

(2007) David O'Hagan   CHEMICAL SOCIETY REVIEWS

Fluorine in medicinal chemistry

(2007) Sophie Purser et al.   CHEMICAL SOCIETY REVIEWS