A palladium-catalyzed process to construct oxazoles and oxazolines with broad functional-group tolerance has been developed, and the method introduces difluoromethyl groups into heterocycles in a one-pot fashion. This system uses a carbonyl oxygen as the acceptor for the addition of a vinylpalladium intermediate to achieve the cyclization. Oxazoline derivatives are generated as the Z-isomer with high
Enantioselective Catalytic Cyclopropanation–Rearrangement Approach to Chiral Spiroketals
作者:Kuioyng Dong、Raj Gurung、Xinfang Xu、Michael P. Doyle
DOI:10.1021/acs.orglett.1c01113
日期:2021.5.21
A highly enantioselective synthesis of chiral heterobicyclic spiroketals is reported via a “one-pot” cyclopropanation–rearrangement (CP-RA) cascade reaction that is sequentially catalyzed by a chiral Rh(II) catalyst and tetrabutylammonium fluoride (TBAF). Exocyclic vinyl substrates form spirocyclopropanes with tert-butyldimethylsilyl-protected enoldiazoacetates in excellent yields and with excellent