通过扩环和O-H插入反应，将稠合双环和三环β-内酯转化为稠合γ-内酯和3(2H)-呋喃酮。

Transformation of fused bicyclic and tricyclic beta-lactones to fused gamma-lactones and 3(2H)-furanones via ring expansions and O-H insertions.

作者信息

Zhang Wei, Romo Daniel

机构信息

Department of Chemistry, Texas A&M University, College Station, TX 77842-3012, USA.

出版信息

J Org Chem. 2007 Nov 9;72(23):8939-42. doi: 10.1021/jo7012934. Epub 2007 Oct 12.

DOI:10.1021/jo7012934

PMID:17929975

Abstract

A two-step strategy for conversion of beta-lactones to gamma-lactones and 3(2H)-furanones was developed involving initial acyl C-O cleavage leading to delta-hydroxy-alpha-diazo-beta-ketoesters and beta-ketophosphonates. Subsequent tandem Wolff rearrangement/lactonization of these alpha-diazo intermediates provided cis-fused gamma-lactones efficiently under photolytic or thermolytic conditions. In addition, cis-fused 3(2H)-furanones were obtained by rhodium(II)-catalyzed O-H insertion reactions of the delta-hydroxy-alpha-diazo intermediates.

摘要

开发了一种将β-内酯转化为γ-内酯和3(2H)-呋喃酮的两步策略，该策略首先涉及酰基C-O键断裂，生成δ-羟基-α-重氮-β-酮酯和β-酮膦酸酯。随后，这些α-重氮中间体进行串联Wolff重排/内酯化反应，在光解或热解条件下高效地生成顺式稠合的γ-内酯。此外，通过铑(II)催化的δ-羟基-α-重氮中间体的O-H插入反应获得了顺式稠合的3(2H)-呋喃酮。