Department of Chemistry and Biochemistry, Auburn University, Auburn, AL, 36849, USA.
Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, 90095, USA.
Angew Chem Int Ed Engl. 2020 Jun 22;59(26):10540-10548. doi: 10.1002/anie.202000039. Epub 2020 Apr 22.
We report a dual function asymmetric catalysis by a chiral phosphoric acid catalyst that controls both enantioselective addition of an achiral α-vinyl allylboronate to aldehydes and pseudo-axial orientation of the α-vinyl group in the transition state. The reaction produces dienyl homoallylic alcohols with high Z-selectivities and enantioselectivities. Computational studies revealed that minimization of steric interactions between the alkyl groups of the diol on boron and the chiral phosphoric acid catalyst influence the orientation of α-vinyl substituent of the allylboronate reagent to occupy a pseudo-axial position in the transition state.
我们报告了一种手性磷酸催化剂的双重不对称催化作用，它可以控制手性α-乙烯基烯丙基硼酸酯对醛的对映选择性加成以及过渡态中α-乙烯基基团的伪轴向取向。该反应以高 Z 选择性和对映选择性生成二烯基同型烯丙基醇。计算研究表明，硼上二醇的烷基与手性磷酸催化剂之间的空间位阻相互作用的最小化影响了烯丙基硼酸酯试剂的α-乙烯基取代基在过渡态中占据伪轴向位置的取向。
