NEW METHODS AND REAGENTS IN ORGANIC SYNTHESIS. 30. RING ENLARGEMENT OF CYCLOALKANONES WITH BENZYLSULFONYLDIAZOMETHANE AND CONVERSION OF THE RESULTING HOMOLOGATED 2-BENZYLSULFONYLCYCLOALKANONES TO 1-BENZYLSULFONYL-1-CYCLOALKENES VIA CHELETROPIC RING CONTRACTION

Abstract

Benzylsulfonyldiazomethane can be used for the ring enlargement of cycloalkanones (1) with various ring sizes. The resulting homologated 2-benzylsulfonylcycloalkanones (2) are easily converted to 1-benzylsulfonyl-1-cycloalkenes (4) by bromination followed by cheletropic ring contraction.