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Diastereoselective Synthesis of Cyclopropyl Boronic Esters
31 December 2000 (online)
The conversion of simple 1-alkynes to optically active 2-alkyl-cyclopropan-1-ols is conveniently achieved by a simple protocol. The key step is the cyclopropanation of alkenyl boronic esters derived from (+)-diisopropyl L-tartrate and alkenyl boronic acids. It has been found that best yields could be obtained using diazomethane and palladium(II) acetate as catalyst. The systematic investigation of parameters influencing this reaction led to an improvement of the diastereoselectivity of the transformation.
cyclopropanation - cyclopropyl boronic ester - diazomethane - cyclopropanol - diisopropyl tartrate