环丁醇开环官能化反应:通过C—C键断裂区域选择性构建γ位取代脂肪酮的新策略

Ring Openings of tert-Cyclobutanols: New Strategy towards the Synthesis of γ-Substituted Ketones via C—C Bond Cleavage

环丁醇开环官能化反应是制备γ位取代脂肪酮的重要策略之一。通过区域选择性的C—C键断裂和新化学键(例如:C—C、C—N、C—O、C—F键等)的构建,环丁醇开环反应可以高效地在羰基的γ位引入各种各样的取代基团。环丁醇的开环反应途径主要分为两种:1)通过过渡金属钯和铑催化的β-碳消除反应开环;2)自由基历程的环丁醇单电子氧化开环。本文依据不同的开环反应机理,对环丁醇的开环官能化反应进行了阐述和展望。

Ketone is an important structural moiety in organic chemistry due to its wide occurrence in organic compounds and the highly transformable ability into other functionalities.Therefore,the efficient synthesis of ketones is of great significance.Recently,the ring-opening functionalization of tert-cyclobutanols represents one of the most important approaches to synthesize γ-substituted alkyl ketones.A variety of functional groups can be efficiently introduced to the γ-position of carbonyl via the regioselective C—C bond cleavage and a new chemical bond（C—C,C—N,C—O,C—F,etc.） formation.Two major pathways might be involved in the ringopening reactions of tert-cyclobutanols：a） transition metals,such as Pd（Ⅱ） and Rh（Ⅰ）,catalyzed β- carbon elimination of tert-cyclobutanols,and b） radical-mediated ring opening via the single electron oxidation of tertcyclobutanols.The recent advances in the ring openings of tert-cyclobutanols and the related mechanistic details are described in this review.