Convenient Access to Functionalized Vinylcyclopentenols from Alkynyloxiranes
摘要:
beta,gamma-Alkynyl aldehydes, generated in situ by treatment of alkynyloxiranes with a catalytic amount of Sc(OTf)(3) or BF3 center dot OEt2, are effectively trapped by a variety of allyl nucleophiles to afford homopropargylic homoallylic alcohols in good yield and selectivity. Such products are used as substrates for the synthesis of functionalized vinylcyclopentenols via enyne metathesis.
3-癸二乙基二羰基二羰基(10)的对映选择性巴豆基硼酸酯为立体化学定义的1,6-烯炔二乙基六羰基复合物(12、13)提供了一条非常便捷的途径,该化合物经历了高度非对映选择性的分子内Pauson-Khand环化成双环辛烯酮14和15(90%) ee 15)。还报道了与母体3-癸醛5相比,烯丙基硼化10中的对映选择性的机械上显着的逆转。