Biphenyl-derived phosphepines as chiral nucleophilic catalysts: enantioselective [4+1] annulations to form functionalized cyclopentenes.

ABSTRACT: Because of the frequent occurrence of cyclopentane subunits in bioactive compounds, the development of efficient catalytic asymmetric methods for their synthesis is an important objective. Introduced herein is a new family of chiral nucleophilic catalysts, biphenyl-derived phosphepines, and we apply them to an enantioselective variant of a useful [4+1] annulation. A range of one-carbon coupling partners can be employed, thereby generating cyclopentenes which bear a fully substituted stereocenter [either all-carbon or heteroatom-substituted (sulfur and phosphorus)]. Stereocenters at the other four positions of the cyclopentane ring can also be introduced with good stereoselectivity. An initial mechanistic study indicates that phosphine addition to the electrophilic four-carbon coupling partner is not the turnover-limiting step of the catalytic cycle.

SUBMITTER: Ziegler DT 

PROVIDER: S-EPMC4433032 | biostudies-literature | 2014 Nov

REPOSITORIES: biostudies-literature