By a sequence comprising asymmetric hydroboration, boron-zinc exchange, and transmetalation with copper, allylations, alkynylations, and allenylations of unsaturated ketals or acetals can be performed with good enantioselectivities (see scheme, (-)-IpcBH2 =(-)-isopinocampheylborane, TMS=Me3 Si). The products correspond to a formal Michael addition with inversion of polarity.
通过包括不对称
硼氢化,
硼锌交换和与
铜的
金属转移的序列,可以以良好的对映选择性进行不饱和
缩酮或
乙缩醛的烯丙基化,炔基化和烯丙基化(参见方案,(-)-IpcBH2 =(-)-异op基异戊基
硼烷, TMS = Me3 Si)。产物对应于具有极性反转的正式迈克尔加成。