描述了高度区域和立体选择性的分子内[1,5]-氢转移过程。用BF3 x OEt2处理γ-苄基保护的Co2(CO)6-α,γ-炔二醇可提供双均炔丙基醇。反应在几秒钟内发生,可耐受多种功能,并提供良好的收率。当醚基位于立体化学定义的碳原子上时,重排会以高立体选择性发生,从而将甲醇中心的手性转移至新创建的立体中心。当存在另外的苄基醚时,苄氧基的裂解是完全区域选择性的。评价了该新方法在密集取代的底物中的范围和局限性,还描述了可能的竞争反应和/或立体化学影响。
The synthesis of pseudomycin C′ via a novel acid promoted side-chain deacylation of pseudomycin A
作者:Michael J Rodriguez、Matthew Belvo、Robert Morris、Douglas J Zeckner、William L Current、Roberta K Sachs、Mark J Zweifel
DOI:10.1016/s0960-894x(00)00613-2
日期:2001.1
The gamma hydroxyl present in the aliphatic side chain of the natural products pseudomycin A and C' provided a unique handle for the pH dependent side-chain deacylation. Low pH reaction conditions were used to cleave the side chain with minimal degradation of the peptide core. The pseudomycin nucleus intermediate obtained from the deacylation of pseudomycin A was pivotal in the synthesis of novel side-chain analogues. A practical synthesis of a minor fermentation factor pseudomycin C' and related analogues is reported. (C) 2001 Elsevier Science Ltd. All rights reserved.
Enantiocontrolled Synthesis of Trialkyl-Substituted Stereogenic Carbons. A General Route to <i>cis-</i>3,5-Dialkyl γ-Lactones
作者:David Díaz、Víctor S. Martín
DOI:10.1021/ol991287b
日期:2000.2.1
[GRAPHICS]Lewis acid treatment of tertiary Co-2(CO)(6)-propargylic alcohols having a stereochemically defined benzyloxy group at the gamma-benzyl position yielded after cobalt demetalation sec-dialkyl bishomopropargylic alcohols in good yields. The reaction is highly stereoselective and predictable, providing pure stereoisomers. The use of benzyl-alpha,alpha'-d(2) ethers permitted the stereoselective d-labeling of methines and methylenes, Very simple chemical manipulations provided a general methodology to obtain the enantiomers of 3,5-dialkyl-gamma-lactones.
THIJS L.; WAANDERS P. P.; STOKKINGREEF E. H. M.; ZWANENBURG B., REC. TRAV. CHIM. PAYS-BAS, 105,(1986) N 9, 332-337
作者:THIJS L.、 WAANDERS P. P.、 STOKKINGREEF E. H. M.、 ZWANENBURG B.