Transposition des bromo-2 benzopropionates d'ethyle, substitues en α par un groupe acetyl ou cyano, en acetyl-2 et cyano-2 benzopropionate d'ethyle。合成这些 d'oxo-3 cyclanecarboxylates d'alkyle a partir de β-cetoesters; 例如,l'iodomethyl-2 oxo-2 cyclopentanecarboxylate d'ethyle 导管 a l'oxo-3 cyclohexcarboxylate d'ethyle
A novelfreeradical initiated ring expansion of haloalkyl β-keto esters is described. Following alkylation of the β-keto ester with the appropriate dihalide, the resulting halide is treated at reflux with tri-n-butyltin hydride. Rearrangement to the homologated γ-keto ester occurs smoothly. An oxy radical intermediate is proposed for the reaction.
Synthesis of fused bicyclic rings by tandem radical ring expansion/cyclization: Evaluating competing intramolecular reactions
作者:Cunxiao Wang、Xin Gu、Marvin S. Yu、Dennis P. Curran
DOI:10.1016/s0040-4020(98)00467-0
日期:1998.7
and three-carbon “Dowd-Beckwith” ringexpansions of cyclopentanones and cyclohexanones are generally successful, but tandem expansion/cyclization reactions can be compromised by competing processes. An evaluation of the competition between ringexpansion, 1,5-hydrogen transfer, and 6-exo cyclization provides information on how to design successful tandem expansion cyclization sequences.
Free radical ring expansion by three and four carbons
作者:Paul Dowd、Soo Chang Choi
DOI:10.1021/ja00255a071
日期:1987.10
Nouvelle methode d'agrandissement de cycles de β-ceto esters a 5, 6, 7 carbones par une reaction radicalaire regioselective pour acceder a des cycles a 8, 9, 10, 11 atomes de carbone
Nouvelle methode d'agrandissement de Cycles de β-cetoesters a 5, 6, 7 carbones par une 反应激进分子区域选择性倾倒剂 a des Cycles a 8, 9, 10, 11 atomes de carbone
Environmentally friendly TPDS-mediated free radical ring expansion of α-haloalkyl cyclic β-keto esters
作者:Masaaki Sugi、Hideo Togo
DOI:10.1016/s0040-4020(02)00241-7
日期:2002.4
Reactivities of tetraphenyldisilane (TPDS), tris(trimethylsilyl)silane, and tributyltin hydride in the radicalringexpansion of α-haloalkyl cyclic β-keto esters were examined. Among these reagents, TPDS was found most effective for the preparation of medium-sized cyclic compounds in terms of yields and ring-expansion/reduction selectivity.