Diastereospecific nazarov cyclization of fully substituted dienones: generation of vicinal all-carbon-atom quaternary stereocenters.

ABSTRACT

No vacancy Fully substituted dienones that are highly polarized by a vinylogous carbonate group were found to undergo a remarkably rapid and diastereospecific Nazarov cyclization that led to cyclopentenones with vicinal all-carbon-atom quaternary centers (see example; SEM=2-(trimethylsilyl)ethoxymethyl, Tf=trifluoromethanesulfonyl).