2006

Oxocarboxylic acids and estersQ 0460 Catalytic Addition Methods for the Synthesis of Functionalized Diazoacetoace-

tates and Application to the Construction of Highly Substituted Cyclobutanones. — Efficient Mukaiyama aldol and Mannich addition reactions of diazo-silyl enol ether (I) with aldehydes and imines using low catalytic amounts of scandium triflate are investigated. Copper and lanthanium triflate catalyze the reaction as well, albeit with lower yields and longer reaction times. The synthetic utility of (III) is demonstrated with the highly diastereoselective syntheses of substituted cyclobutanones (VI) and (VII). — (DOYLE*, M. P.; KUNDU, K.; RUSSELL, A. E.; Org. Lett. 7 (2005) 23, 5171-5174; Dep. Chem. Biochem., Univ. Md., College Park, MD 20742, USA; Eng.) — R. Steudel

12- 092