Chiral Nonracemic α-Alkylidene and α-Silylidene Cyclopentenones from Chiral Allenes Using an Intramolecular Allenic Pauson−Khand-Type Cycloaddition
作者:Kay M. Brummond、Angela D. Kerekes、Honghe Wan
DOI:10.1021/jo016305t
日期:2002.7.1
effected a transfer of chirality from a chiral nonracemic allene to an alpha-alkylidene and an alpha-silylidene cyclopentenone. The molybdenum-mediated examples possessing a silyl group on the terminus of the allene show good facial selectivities, but isomerization of the (E)-silylidene cyclopentenone to the (Z)-silylidene cyclopentenone occurs upon purification of these products. Alternatively, an alkyl group