Divergent Reactivity via Cobalt Catalysis: An Epoxide Olefination

作者：Jamieson Megan L; Hume Paul A; Furkert Daniel P^*; Brimble Margaret A^*

来源：Organic Letters, 2016, 18(3): 468-471.

DOI：10.1021/acs.orglett.5b03514

Cobalt salts exert an unexpected and profound influence on the reactivity of epoxides with dimethylsulfoxonium methylide. In the presence of a cobalt catalyst, conditions for epoxide to an oxetane ring expansion instead deliver homoallylic alcohol products, corresponding to a two-carbon epoxide homologation/ring-opening tandem process. The observed reactivity change appears to be specifically due to cobalt salts and is broadly applicable to a variety of epoxides, retaining the initial stereochemistry. This transformation also provides operationally simple access to enantiopure homoallylic alcohols from chiral epoxides without use of organometallic reagents. Tandem epoxidation-homologation of aldehydes in a single step is also demonstrated.

• 出版日期2016-2-5