Development of new synthetic reactions based on the reactions of α, β-epoxysilanes and nucleophiles

本研究的目的是开发基于α，β-环氧硅烷与亲核试剂反应的新合成反应。1.八元碳环的立体专一性构筑当γ-丙烯酰基酰基硅烷与乙烯基锂反应时，由乙烯基锂的1，2-加成物经Brook重排生成的1，2-二乙烯基环丁二醇中间体经阴离子氧-Cope重排，得到单一非对映体的环辛烯酮衍生物。此外，我们还发现了一种更通用的碳环化合物的合成方法，该方法涉及由β-甲氧羰基酰基硅烷和乙烯基锂制备的γ-乙烯基-γ-甲硅烷基-γ-内酯与乙烯基锂的反应.α，β-环氧-β-硅基丙醛的O-硅氰醇衍生物与碱在烷基化试剂存在下的反应α，β-环氧-β-硅基丙醛的O-硅氰醇衍生物与强碱如LDA、NHMDS在烷基碘存在下反应，以优异的产率得到2，4-双（硅氧基）-3-丁烯腈的2-烷基化衍生物，为单一异构体。没有得到O-烷基化和4-烷基化产物的事实表明，涉及质子夺取/环氧开环/布鲁克重排/烯丙基重排/烷基化的串联过程将以协同的方式发生。在反应中使用容易获得的光学活性环氧化物似乎非常有希望的季手性中心的建设，将是进一步研究的主题。

The objective of this study has been to develop new synthetic reactions based on the reaction of α, β-epoxysilanes with a nucleophile.1. Stereospecific Construction of Eight-Membered CarbocyclesWhen γ-acryloylacylsilane was treated with vinyllithium, a cyclooctenone derivative was obtained as a single diastereomer via an anionic oxy-Cope rearrangement of 1, 2-divinylcyclobutanediol intermediate generated by way of Brook rearrangement of the 1, 2-adduct of the vinyllithium. Furthermore, we found a more versatile methodology for the synthesis of the carbocycles, which involves the reaction of γ-vinyl-γ-silyl-γ-lactones, prepared from β-methoxycarbonyacylsilane with vinyllithium, with vinyllithium.2. Reaction of O-silyl Cyanohydrin derivatives of α, β-Epoxy-β-silylpropanal with Bases in the Presence of Alkylating AgentsReaction of O-silyl cyanohydrin derivatives of α, β-Epoxy-β-silylpropanal with a strong base such as LDA, NHMDS in the presence of alkyl iodide afforded 2-alkylated derivatives of 2, 4-bis (siloxy)-3-butenenitrile as a single isomer in excellent yields. The fact that no O-alkylated and 4-alkylated products were obtained suggests that the tandem processes involving proton abstraction/epoxide ring opening/Brook rearrangement/allylic rearrangement/alkylation would occur in a concerted manner. The use of readily available optically active epoxides in the reaction seems very promising for construction of quaternary chiral centers and will be the subject of further studies.