Methyltrioxorhenium as Catalyst of a Novel Aldehyde Olefination

From aldehydes or cyclic ketones, diazoalkanes, and tertiary phosphanes , olefins may be prepared according to Equation (a) with MTO as catalyst. In particular, diazoacetates and ‐malonates (R 2 , R 3 H, CO 2 ,Et, or 2 × CO 2 Me) can be transformed into olefins with aliphatic and aromatic aldehydes (R 1 i Pr, trans ‐PhCHCH, Ph, 4‐NO 2 C 6 H 4 , etc.). Readily accessible starting materials, easy handling, mild reaction conditions, and good yields characterize the new synthesis method. (R′Ph, 3‐C 6 H 4 SO 3 Na, n Bu.)