报道了对-fragransin C 1的首次不对称合成。关键步骤涉及通过化学选择性生成苄基碳正离子形成分子内C–O键(呋喃环形成),从而导致2,3-抗-3,4- syn -4,5-抗四氢呋喃部分为单个非对映异构体产量高。我们的合成证实,对-fragransin C 1具有2 R,3 R,4 S,5 S构型。
Highly Enantioselective Claisen Rearrangement of Imidates Derived from Primary Allyl Alcohols
作者:Peter Metz、Benno Hungerhoff
DOI:10.1021/jo970123a
日期:1997.6.1
A highly enantioselective and diastereoselective Claisen rearrangement of N-arylimidates derivedfrom an axially chiral binaphthylamine auxiliary is reported. Upon deprotonation of the imidates with lithium diethylamide, the resultant azaenolates rearrange at 0 degrees C to give anti alpha,beta-disubstituted, gamma,delta-unsaturated N-binaphthyl amides. A iodolactonization/zinc reduction sequence readily
stereoselective construction of (3R,4S,5R)- and (3R,4S,5S)-trisubstituted γ-butyrolactones 3 and 4 from (2R,3R)-2,3-dimethyl-4-pentenoic acid derivative 7, which was readily obtained via stereoselective conjugate addition of vinylmagnesium chloride to a chiral α,β-unsaturated N-acyl oxazolidinone (Evans’ auxiliary) followed by α-methylation.
Acyloxylactonisations mediated by lead tetracarboxylates
作者:Ian F. Cottrell、Andrew R. Cowley、Laura J. Croft、Lauren Hymns、Mark G. Moloney、Ewan J. Nettleton、H. Kirsty Smithies、Amber L. Thompson
DOI:10.1016/j.tet.2009.01.042
日期:2009.3
The reaction of lead(IV) tetracarboxylates with carboxylic acids containing unsaturated side chains has been found to give acyloxy lactone products in a diastereoselective process; the reaction can be extended to lead(IV) tetrazolates to give the analogous outcome. Mechanistic implications of these results are discussed. (C) 2009 Elsevier Ltd. All rights reserved.
Corey; Lee, Duck-Hyung, Journal of the American Chemical Society, 1991, vol. 113, # 10, p. 4026 - 4027
作者:Corey、Lee, Duck-Hyung
DOI:——
日期:——
TSUNODA, TETSUTO;SASAKI, OSAMU;ITO, SHO, TETRAHEDRON LETT., 31,(1990) N, C. 731-734