Article
Chemistry, Multidisciplinary
Ryan A. Woltornist, David B. Collum
Summary: The enolization of ketones by sodium hexamethyldisilazide (NaHMDS) displays significant solvent and substrate dependence, leading to varied reaction rates, stereoselectivity, and mechanisms. Different solvents result in different products and reaction pathways for enolization of ketones, highlighting the complex interplay between NaHMDS, solvents, and substrates.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Multidisciplinary
Yueming Wu, Min Zhou, Kang Chen, Sheng Chen, Ximian Xiao, Zhemin Ji, Jingcheng Zou, Runhui Liu
Summary: The study demonstrates that lithium/sodium/potassium hexamethyldisilazide can initiate polymerization on NNCAs at a substantially faster rate, especially for NNCAs with bulky N substitution groups. This accelerated polymerization can increase the structural diversity and applications of polypeptoids as synthetic mimics of polypeptides.
CHINESE CHEMICAL LETTERS
(2021)
Article
Chemistry, Multidisciplinary
Qiulin You, David B. Collum
Summary: This study reveals the solvent-dependent reactivity of sodium hexamethyldisilazide (NaHMDS) towards carbon-centered electrophiles, including reactions that are not well-described in the literature. Using NMR spectroscopic studies, kinetic studies, and computational studies, the mechanistic preferences for simple aryl carboxamides in different solvents and the prevalence of dimer-based chemistry in THF solution are elucidated.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Physical
Bing Zhang, Xin Xu, Lei Tao, Zhenyang Lin, Wanxiang Zhao
Summary: In this study, an efficient rhodium-catalyzed deoxygenative borylation of ketones was reported to synthesize alkylboronates, with regioselectivity controlled by the choice of ligand. Different steric effects of ligands were found to be responsible for product selectivity. The reaction pathway involves an alkene intermediate which undergoes regiodivergent hydroboration to afford linear and branched alkylboronates, or sequential dehydrogenative borylation and hydroboration to deliver triboronates.
Article
Chemistry, Multidisciplinary
Monika Pareek, Raghavan B. Sunoj
Summary: The study investigates the nature of potential active catalyst, energetic features of the catalytic cycle, and the origin of high enantioselectivity in the asymmetric allylic alkylation reaction of alpha,alpha-disubstituted aldehydes. It is found that the in-situ formation of a Rh-phosphonate likely acts as an active catalyst, leading to the formation of a quaternary stereogenic center. The stereochemical preference for the formation of product on the re face is attributed to improved noncovalent interactions and less distortion in the enantiocontrolling C-C bond formation transition state. The computed enantioselectivity and activation barrier are in good agreement with experimental values.
Article
Chemistry, Inorganic & Nuclear
Jihong Xu, Yiying Yang, Xia Zhao, Chengbu Liu, Dongju Zhang
Summary: The study developed an Ir-III/Ni-II metallaphotoredox-catalyzed difluoromethylation strategy and used CHF2Br as the reagent. The computational calculations showed that a special dual catalysis mechanism promoted the coupling of C(sp(2))-C(sp(3)), and rationalized the stoichiometric effect of CHF2Br in reactions with aryl bromides containing different substituents.
INORGANIC CHEMISTRY
(2021)
Article
Chemistry, Organic
DeGuang Liu, ZheYuan Xu, MingQiang Liu, Yao Fu
Summary: The study reveals the mechanism of Rh(II)-catalyzed lactonization reaction through density functional theory calculations, involving coordination exchange, C-H bond activation, carboxylation, protonation, and lactonization steps. The key steps are carboxylation and protonation, with the pKa value of the base predicting the energy barrier of the reaction.
ORGANIC CHEMISTRY FRONTIERS
(2022)
Article
Chemistry, Organic
Nan-Nan Li, Meng Li, Jia-Ni Gao, Zhong Zhang, Jian-Bo Xie
Summary: This study systematically investigates the dearomatic silylation of aryl carbonyl compounds using Mg and the TMSCl/NMP adduct. The protocol shows a wide range of substrate scope and the products are demonstrated to be versatile substrates in various transformations. The detailed mechanism is presented, including the proposal of an unusual silicon dianion intermediate.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Inorganic & Nuclear
Siyuan Zhai, Milena Petkovic, Dragoslav Vidovic
Summary: In this work, it is shown that three-coordinate mono-aminoboranes are not efficient hydroboration reagents unless they can form four-coordinate analogues. It is also demonstrated that imine-BH3 adduct(s) and mono-aminoboranes are not key intermediates in the Me2S-BH3 catalyzed hydroboration of imines. Instead, the Clark mechanism is believed to be mainly responsible for the observed hydroboration reactions in both of these reported studies.
Article
Chemistry, Organic
Ravinder Kumar, Jai Parkash, Raj Kamal, Vipan Kumar, Sangeeta Saini
Summary: This study investigates and validates oxidative 1,2-aryl C-C migration in variegated alpha,beta-unsaturated diaryl ketones, leading to the synthesis of alpha-aryl-beta,beta-ditosylm ketones. The mechanism and generality of this migration were supported by computational studies, demonstrating a novel strategy for regioselective synthesis of various aryl compounds.
ASIAN JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Mithun Chakraborty, Gaddam Mahesh, Omkar R. Nakel, Gautamee Chavda, Susarla Anusha, Gangarajula Sudhakar
Summary: A novel method has been developed for the preparation of highly substituted functionalized indenes through a two-step reaction, resulting in good to excellent yields.
Article
Chemistry, Organic
Domenic P. Pace, Raphael Robidas, Uyen P. N. Tran, Claude Y. Legault, Thanh Vinh Nguyen
Summary: A practical and mild catalytic method for the synthesis of substituted pyrans and furans using molecular iodine has been reported, offering a facile alternative under solvent-free conditions at ambient temperature and atmosphere. Mechanistic insights into this seemingly simple reaction were revealed through a combination of experimental studies and density functional theory calculations.
JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Physical
Hanlin Gan, Liang Peng, Feng Long Gu
Summary: The mechanism of Cu(I)-catalyzed domino reaction for synthesizing 1-aryl-1,2,3-triazole was investigated using DFT calculations, revealing four consecutive reactions and highlighting the importance of aryl azide formation and C-N bond coupling steps. Enhanced d(Cu)- orbital interaction plays a crucial role in the oxidative addition of aryl bromide onto cuprate-triazole anion, lowering the energy barrier.
CATALYSIS SCIENCE & TECHNOLOGY
(2021)
Article
Chemistry, Multidisciplinary
Subhash Garhwal, Jatin Panda, Natalia Fridman, Amir Karton, Graham de Ruiter
Summary: Directing groups are crucial for controlling the selectivity of C-H bond activation. In this study, we show that the nature of the directing group (ketone, ester, or amide) influences the C-H activation process for iron, leading to distinct cis- and trans-isomers of the corresponding iron hydrides.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Xiang Liu, Cai-Yu He, Hao-Nan Yin, Chengping Miao, Xue-Qiang Chu, Weidong Rao, Hao Xu, Xiaocong Zhou, Zhi-Liang Shen
Summary: A nickel-catalyzed cross-electrophile coupling of triazine esters with aryl bromides in the presence of magnesium and lithium chloride has been developed. The reactions proceed efficiently at room temperature through C-O bond activation, providing a variety of diaryl ketones in moderate to good yields with wide functional group tolerance.
CHINESE JOURNAL OF CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Yuhui Zhou, Janis Jermaks, Ivan Keresztes, Samantha N. MacMillan, David B. Collum
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2019)
Article
Chemistry, Organic
Zirong Zhang, David B. Collum
JOURNAL OF ORGANIC CHEMISTRY
(2019)
Article
Chemistry, Organic
Yun Ma, Russell F. Algera, Ryan A. Woltornist, David B. Collum
JOURNAL OF ORGANIC CHEMISTRY
(2019)
Article
Chemistry, Multidisciplinary
Joshua J. Gladfelder, Santanu Ghosh, Masa Podunavac, Andrew W. Cook, Yun Ma, Ryan A. Woltornist, Ivan Keresztes, Trevor W. Hayton, David B. Collum, Armen Zakarian
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2019)
Article
Chemistry, Multidisciplinary
Raphael Bigler, Kyle A. Mack, Jeff Shen, Paolo Tosatti, Chong Han, Stephan Bachmann, Haiming Zhang, Michelangelo Scalone, Andreas Pfaltz, Scott E. Denmark, Stefan Hildbrand, Francis Gosselin
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2020)
Article
Chemistry, Multidisciplinary
Ryan A. Woltornist, David B. Collum
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2020)
Article
Chemistry, Organic
Ryan A. Woltornist, David B. Collum
Summary: The study reports solution structures of sodium hexamethyldisilazide solvated by over 30 standard solvents, revealing ligand-modulated aggregation to give a mixture of dimers, monomers, triple ions, and ion pairs. Experimental results show that the relative abilities of solvents to compete in binary mixtures often match conventional wisdom, with some exceptions and evidence of both competitive and cooperative solvation phenomena. Crystal structures of a NaHMDS cryptate ion pair and a 15-crown-5-solvated monomer are included in the comparison with other similar compounds.
JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Yun Ma, Ryan A. Woltornist, Russell F. Algera, David B. Collum
Summary: This study compared the catalytic effects of PMDTA and TMEDA, highlighting the importance of trifunctionality and kappa(2)-kappa(3) hemilability. PMDTA showed remarkable acceleration in reactions, with up to >30-fold accelerations using 10 mol % PMDTA. Additionally, solid-liquid phase-transfer catalysis was explored as a means to optimize the catalysis and explore the advantages of heterogeneous reaction conditions.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Multidisciplinary
Ryan A. Woltornist, David B. Collum
Summary: The enolization of ketones by sodium hexamethyldisilazide (NaHMDS) displays significant solvent and substrate dependence, leading to varied reaction rates, stereoselectivity, and mechanisms. Different solvents result in different products and reaction pathways for enolization of ketones, highlighting the complex interplay between NaHMDS, solvents, and substrates.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Applied
Jie Xu, Cheol K. Chung, Andrew McClory, Kyle A. Mack, Michael E. Dalziel, Alec Fettes, Kyle Clagg, Ngiap-Kie Lim, Georg Wuitschik, Christian Jenny, Laure Finet, Michael Kammerer, Haiming Zhang, Remy Angelaud, Francis Gosselin
Summary: GDC-9545, a selective estrogen receptor degrader, is being developed as a treatment for ER+/HER2- breast cancer. A robust and efficient manufacturing process has been developed to produce GDC-9545.
ORGANIC PROCESS RESEARCH & DEVELOPMENT
(2022)
Article
Chemistry, Organic
Yun Ma, Nathan M. Lui, Ivan Keresztes, Ryan A. Woltornist, David B. Collum
Summary: The preparation, structure, physical properties, and reactivities of sodium isopropyl(trimethylsilyl)amide (NaPTA) were investigated. NaPTA showed different solubilities in various solvents, with good stability in neat THF. Compared to LDA, NaPTA exhibited higher reactivities in metalations of different compounds. The study also explored the applications of NaPTA in THF and its metalation reactions with various substrates.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Jie Xu, Samantha Grosslight, Kyle A. Mack, Sierra C. Nguyen, Kyle Clagg, Ngiap-Kie Lim, Jacob C. Timmerman, Jeff Shen, Nicholas A. White, Lauren E. Sirois, Chong Han, Haiming Zhang, Matthew S. Sigman, Francis Gosselin
Summary: An efficient asymmetric synthesis of a potent KRAS G12C covalent inhibitor, GDC-6036, was reported. The synthesis involved a highly selective Negishi coupling and a series of reaction sequences, leading to the desired compound with a 40% overall yield from the starting materials.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Multidisciplinary
Jordan J. Dotson, Lucy van Dijk, Jacob C. Timmerman, Samantha Grosslight, Richard C. Walroth, Francis Gosselin, Kurt Puentener, Kyle A. Mack, Matthew S. Sigman
Summary: A machine learning workflow is utilized to optimize catalytic reactions with chiral bisphosphine ligands, resulting in the prediction and validation of improved ligands for multiple reaction objectives. This provides a general strategy for reaction optimizations controlled by bisphosphine ligands.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Nathan M. Lui, Samantha N. MacMillan, David B. Collum
Summary: This paper examines the mechanism of alkylation and the origin of stereoselectivity using Camphorsultam-based lithium enolates. The structures of the enolates are found to be dependent on the solvent and substrate, and the stereochemistry of aggregation is extensively analyzed. The stereochemistry is determined by the chirality within the sultam ring.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Multidisciplinary
Qiulin You, David B. Collum
Summary: This study reveals the solvent-dependent reactivity of sodium hexamethyldisilazide (NaHMDS) towards carbon-centered electrophiles, including reactions that are not well-described in the literature. Using NMR spectroscopic studies, kinetic studies, and computational studies, the mechanistic preferences for simple aryl carboxamides in different solvents and the prevalence of dimer-based chemistry in THF solution are elucidated.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
