Article
Chemistry, Analytical
Asaad S. Mohamed, Osama M. Habib, Nouria A. Al-Awadi
Summary: Flash vacuum pyrolysis of various aryl propargyl ethers with different substituents was investigated, and mechanisms for some reactions were proposed.
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
(2022)
Article
Chemistry, Multidisciplinary
Itai Massad, Ilan Marek
Summary: Coates first investigated the [3,3]-sigmatropic rearrangement of allylic vinyl acetals nearly four decades ago, which features a versatile monoprotected 1,5-dicarbonyl motif. The synthetic elusive nature of the substrates has hindered widespread application, but recent studies have shown that key allylic vinyl acetals can be efficiently generated through alkene isomerization.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Organic
Lijun Chang, Cheng Cai, Ran Chen, Jianhui Chen, Yanshu Luo, Yuanzhi Xia
Summary: The ligand-controlled cobalt-catalyzed isomerization and reductive C-O bond cleavage of allylic ethers are reported in this paper. With an amido-diphosphine ligand (PNP), the isomerization reaction proceeds smoothly, resulting in a series of trisubstituted enol ethers with high stereoselectivity. By using a phosphine-amido-oxazoline ligand (PAO), the reaction switches to reductive C-O bond cleavage in the presence of HBpin. Preliminary mechanistic studies suggest that both reactions proceed through cobalt-hydride mediated alkene insertion to form an alkylcobalt species, which is then selectively eliminated by the ligand.
ORGANIC CHEMISTRY FRONTIERS
(2023)
Article
Biochemistry & Molecular Biology
Yoko Hamada, Rio Matsunaga, Tomoko Kawasaki-Takasuka, Takashi Yamazaki
Summary: The CF3 group was found to significantly influence the base-mediated proton shift in propargylic or allylic alcohols with high CF3 content, allowing for the synthesis of alpha, beta-unsaturated or saturated ketones. This method was applied to the synthesis of allyl vinyl ethers in this study, achieving the desired rearrangement through proton shift.
Article
Chemistry, Organic
Chih-Hao Luo, Pei-Ling Wang, Che-Chien Chang
Summary: Various N-(2-bromo-allyl) benzamides were used as starting materials for studying vinyl radical cyclization reactions, which produced beta-aryl-gamma-lactams without affecting the carbonyl group. The cascade radical reaction led to the synthesis of alpha,beta-unsaturated-beta-aryl-gamma-lactam derivatives, with the effects of substituents on the amino and aryl groups examined.
JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Applied
Camille Van Wesemael, Nicolas Brach, Mihaela Gulea, Gaelle Blond
Summary: A series of 3-allenyl benzo[b]thiophenes were synthesized through a gold(I)-catalyzed domino reaction. The process involves a 5-endo-dig cyclization with C S bond formation and consecutive S-to-C propargyl migration via [3,3]-sigmatropic Claisen rearrangement. Various fused O-heterocycles can be obtained from a substrate bearing a 3-butynol moiety via intramolecular hydroalkoxylation. The gold-mediated 1,3-migration involving allenyl to propargyl rearrangement is also described.
ADVANCED SYNTHESIS & CATALYSIS
(2022)
Article
Chemistry, Multidisciplinary
Lifeng Wang, Yuqiao Zhou, Zhishan Su, Fengcai Zhang, Weidi Cao, Xiaohua Liu, Xiaoming Feng
Summary: This study discovered the thermal para-Claisen rearrangement of naphthyl 1-propargyl ethers and elucidated its mechanism for constructing stereogenic centers. By controlling the reaction conditions and catalyst selection, organic molecules with different substitutions can be efficiently synthesized.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Organic
Xiao-Qian Zhang, Congdi Zhang, Zhiyou Hu, Youliang Wang
Summary: The gold-catalyzed divergent additions of trans-2-butene-1,4-amino alcohols' N-H and O-H groups to alkynes, followed by a cascade (Aza-) Claisen rearrangement/cyclization sequence, has been reported. This reaction produces functionalized dihydropyrrole and dihydrofuran products.
Article
Chemistry, Organic
Antonia Rinaldi, Vittoria Lange, Dina Scarpi, Ernesto G. Occhiato
Summary: In this study, the synthesis of (+/-)-epi-jungianol was successfully achieved through a gold(I)-catalyzed propargyl Claisen rearrangement/hydroarylation cascade reaction of suitably substituted propargyl vinyl ethers. Two different routes were compared, with the one involving substrates with less substitution on the vinyl moiety providing a higher overall yield despite requiring two additional steps. Additionally, a method for preparing acid-sensitive propargyl vinyl ethers with an alpha-alkyl-substituted vinyl moiety and their reactivity under gold catalysis was reported.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Applied
Wei-Jung Chiu, Jin-Yu Chen, Shih- Liu, Indrajeet J. Barve, Wan-Wen Huang, Chung-Ming Sun
Summary: A one-pot, two-step synthesis of isoquinoline-fused isoquinolines from alpha-amino acid esters and 2-alkynyl benzaldehydes is reported. The strategy involves an unconventional Pictet-Spengler reaction and subsequent gold-catalyzed intramolecular hydroamination. The scope of this strategy is further extended to prepare multisubstituted isoquinoline-fused isoquinolines.
ADVANCED SYNTHESIS & CATALYSIS
(2021)
Article
Chemistry, Multidisciplinary
Jing Liu, Yusheng Yang, Weiming Shi, Zhi-Xiang Yu
Summary: We present computational evidence for a metalla-Claisen rearrangement (MCR) in the gold-catalyzed [4+2] cycloaddition reaction of yne-dienes. The reaction proceeds through exo cyclopropanation, followed by MCR and reductive elimination. The presence of a cyclopropane moiety formed in the initial step greatly facilitates the MCR process. Additionally, we explore the significance of the combination of tether group and terminal substituent on alkyne in the yne-diene substrates. We also investigate whether an MCR mechanism is involved in the rhodium-catalyzed [4+2] reaction of yne-dienes. These findings and insights represent a significant advancement in the field of catalysis.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Organic
Fei-Fei Zou, Zhen Luo, Yu-Ting Yang, Xin Zhuang, Chuan-Ming Hong, Zheng-Qiang Liu, Wan-Fang Li, Qing-Hua Li, Tang-Lin Liu
Summary: A regio- and chemoselective sulfonylation method was developed for the synthesis of multi-substituted allenyl sulfones using sulfinamides as the sulfonyl sources. The use of 1,1,1,3,3,3-hexafluoroisopropanol (HFIP) as the solvent enabled the transformation to proceed under mild conditions without the need for additional catalysts or oxidants.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Physical
Bing Li, Yanshu Luo, Min Liu, Yuanzhi Xia, Changkun Li
Summary: The abnormal Claisen rearrangement of phenyl allyl ether with the gamma-alkyl group is well-known, but its asymmetric version has not been reported before. In this study, a highly regio- and enantioselective allylic alkylation of 4-hydroxycoumarin was developed as a formal abnormal Claisen rearrangement. Chiral 4-hydroxycoumarins with 3-allyl groups were synthesized with high yield and enantiomeric excess using rhodium catalyst and chiral bioxazolinephosphine ligand. Experimental and theoretical investigations revealed that the stereospecific rearrangement occurs through the reversible formation of a kinetically favored cis-disubstituted spirocyclopropane intermediate.
Article
Chemistry, Applied
Yuan Li, Feifei Fang, Jianhui Zhou, Jiyuan Li, Run Wang, Hong Liu, Yu Zhou
Summary: The study developed a beta-hydroxy elimination approach for the synthesis of 2-benzyl substituted isoquinoline N-oxides from secondary propargyl alcohols, achieving moderate to excellent yields (up to 92%) under mild reaction conditions, with good regioselectivity, broad generality, and applicability.
ADVANCED SYNTHESIS & CATALYSIS
(2021)
Article
Chemistry, Multidisciplinary
Rahul Suresh, Itai Massad, Ilan Marek
Summary: The Cope rearrangement of 2,3-divinyloxiranes leads to the formation of 4,5-dihydrooxepines with two contiguous stereocenters, allowing for efficient synthesis of 1,6-dicarbonyl compounds through hydrolysis. Using an Ir-based catalyst enables excellent control over regio- and stereochemistry, providing a promising strategy for the synthesis of these compounds.
Article
Chemistry, Multidisciplinary
Yukimasa Aida, Yu Shibata, Ken Tanaka
CHEMISTRY-A EUROPEAN JOURNAL
(2020)
Article
Chemistry, Multidisciplinary
Jin Tanaka, Yu Shibata, Anton Joseph, Juntaro Nogami, Jyunichi Terasawa, Ryo Yoshimura, Ken Tanaka
CHEMISTRY-A EUROPEAN JOURNAL
(2020)
Article
Chemistry, Multidisciplinary
Shunsuke Suzuki, Yu Shibata, Ken Tanaka
CHEMISTRY-A EUROPEAN JOURNAL
(2020)
Article
Chemistry, Multidisciplinary
Ryo Yoshimura, Ken Tanaka
CHEMISTRY-A EUROPEAN JOURNAL
(2020)
Article
Chemistry, Multidisciplinary
Suzuka Kinoshita, Ryota Yamano, Yu Shibata, Yusuke Tanaka, Kyoichi Hanada, Takashi Matsumoto, Kazunori Miyamoto, Atsuya Muranaka, Masanobu Uchiyama, Ken Tanaka
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2020)
Article
Chemistry, Multidisciplinary
Eiki Tomita, Kodai Yamada, Yu Shibata, Ken Tanaka, Masahiro Kojima, Tatsuhiko Yoshino, Shigeki Matsunaga
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2020)
Article
Chemistry, Multidisciplinary
Yukimasa Aida, Juntaro Nogami, Haruki Sugiyama, Hidehiro Uekusa, Ken Tanaka
CHEMISTRY-A EUROPEAN JOURNAL
(2020)
Article
Chemistry, Multidisciplinary
Juntaro Nogami, Yusuke Tanaka, Haruki Sugiyama, Hidehiro Uekusa, Atsuya Muranaka, Masanobu Uchiyama, Ken Tanaka
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2020)
Article
Chemistry, Multidisciplinary
Li-Hsiang Wang, Norihiko Hayase, Haruki Sugiyama, Juntaro Nogami, Hidehiro Uekusa, Ken Tanaka
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2020)
Article
Chemistry, Organic
Hiroto Takahashi, Yusaku Honjo, Yu Shibata, Yuki Nagashima, Ken Tanaka
Summary: The dienylation of unfunctionalized arenes with 1,6-diynes, possessing aryl groups at the diyne termini, was found to proceed in the presence of an electron-deficient cyclopentadienyl rhodium(III) complex and a stoichiometric amount of silver carbonate. Experimental and theoretical mechanistic studies indicated the possible catalytic role of a (CpRh)-Rh-E(I) complex generated in situ in this reaction.
SYNTHESIS-STUTTGART
(2021)
