Pd-catalyzed 5-endo-trig-type cyclization of β,γ-unsaturated carbonyl compounds: an efficient ring closing reaction to give γ-butenolides and 3-pyrrolin-2-ones
作者:Gan B. Bajracharya、Priti S. Koranne、Rashid N. Nadaf、Randa Kassem Mohamed Gabr、Kazuhiro Takenaka、Shinobu Takizawa、Hiroaki Sasai
DOI:10.1039/c0cc02352c
日期:——
The 5-endo-trig-type cyclization has been performed using a Pd-bis(isoxazoline) catalyst. The present cyclization of beta,gamma-unsaturated carbonylcompounds gave gamma-butenolides and 3-pyrrolin-2-ones in good to excellent yields.
novel Cu(I)-ligand cooperative catalysis. The reaction is enabled by a chiral biphenyl-2-ylphosphine ligand featuring a remote tertiary amino group. Density functional theory studies support the cooperation between the metal center and the ligand basic amino group during the initial soft deprotonation and the key asymmetric γ-protonation. Remarkably, other coinagemetals, that is, Ag and Au, can readily
具有≥96% 对映体过量的 α,β-丁烯内酯是由 β,γ-丁烯内酯通过新型 Cu(I)-配体协同催化合成的。该反应由具有远程叔氨基的手性联苯-2-基膦配体实现。密度泛函理论研究支持金属中心和配体碱性氨基在初始软去质子化和关键不对称γ-质子化过程中的合作。值得注意的是,其他造币金属,即 Ag 和 Au,在这种不对称异构化化学中可以很容易地承担与 Cu 相同的作用。
A convergent asymmetric synthesis of γ-butenolides
作者:Marc Renard、Léon A. Ghosez
DOI:10.1016/s0040-4020(01)00078-3
日期:2001.3
The addition of aldehydes to the new enantiomerically pure lithiated sulfoxide-orthoester 13 yielded gamma -butenolides of high enantiomeric purities after elimination of phenylsulfinic acid. The cyclocondensation with ketones was less stereoselective. This new asymmetric synthesis of gamma -butenolides has been applied to a convergent preparation of the antifungal antibiotic (+)-cerulenin. (C) 2001 Elsevier Science Ltd. All rights reserved.
Examples of highly efficient kinetic resolutions with the bicyclic chiral cyclopentadiene 1 and several selected cyclic dienophiles are reported. In combination with a thermal retro-Diels-Alder process this procedure provides easy access to both enantiomers of these dienophiles.
FRANK-NEUMANN, M.;SEDRATI, M.;VIGNERON, J. -P.;BLOY, V.
作者:FRANK-NEUMANN, M.、SEDRATI, M.、VIGNERON, J. -P.、BLOY, V.