Copper(II)-Catalyzed Tandem Decarboxylative Michael/Aldol Reactions Leading to the Formation of Functionalized Cyclohexenones.

ABSTRACT: This work describes the development of a new single-pot copper(II)-catalyzed decarboxylative Michael reaction between ?-keto acids and enones, followed by in situ aldolization, which results in highly functionalized chiral and achiral cyclohexenones. The achiral version of this Robinson annulation features a hitherto unprecedented Michael reaction of ?-keto acids with sterically hindered ?,?'-substituted enones and provides access to all carbon quaternary stereocenter-containing cyclohexenones (11 examples, 43-83% yield). In addition, an asymmetric chiral bis(oxazoline) copper(II)-catalyzed single-pot Robinson annulation has been devised for preparing chiral cyclohexenones, including some products that contain vicinal stereocenters (5 examples, 65-85% yield, 84-94% ee). This latter protocol has been successfully applied to the enantioselective formation of the oxygenated 10-nor-steroid core from readily available starting materials.

SUBMITTER: Lee J 

PROVIDER: S-EPMC5889748 | biostudies-literature | 2018 Apr

REPOSITORIES: biostudies-literature