Stereo- and enantioselective syntheses of 1,2-oxaborinan-3-enes and δ-boryl-substituted homoallylic alcohols are reported. We developed a practical approach to synthesize α-boryl-substituted allylboronate. This reagent was utilized to generate α,α-disubstituted allylboronates, and such reagents cannot be accessed via the Pd-catalyzed alkene isomerization approach. Chiral Brønsted-acid-catalyzed aldehyde addition with these reagents gave 1,2-oxaborinan-3-enes with excellent stereo- and enantioselectivities. Lewis-acid-catalyzed aldehyde addition also worked well, affording δ-boryl-substituted homoallylic alcohols with high stereoselectivities. The enantioselective variant of the reaction was achieved via a chiral Brønsted-acid-catalyzed aldehyde addition and Pd-catalyzed alkene isomerization approach.

中文翻译：

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1,2-氧杂基聚糖-3-烯和 δ-硼基取代的均烯丙基醇的立体和对映选择性合成


报道了 1,2-氧杂基聚糖-3-烯和 δ-硼基取代的均烯丙基醇的立体和对映选择性合成。我们开发了一种合成 α-硼基取代烯丙基硼酸盐的实用方法。该试剂用于生成 α，α-二取代烯丙基硼酸盐，并且此类试剂无法通过 Pd 催化的烯烃异构化方法获得。与这些试剂进行手性 Brønsted 酸催化的醛加成反应，得到具有优异立体选择性和对映选择性的 1,2-氧杂基聚糖-3-烯。路易斯酸催化的醛加成反应也很好，获得了具有高立体选择性的 δ-硼基取代的均烯丙醇。反应的对映选择性变体是通过手性 Brønsted 酸催化的醛加成和 Pd 催化的烯烃异构化方法实现的。