Chemo- and Enantioselective Pd/B Hybrid Catalysis for the Construction of Acyclic Quaternary Carbons: Migratory Allylation of <i>O</i>-Allyl Esters to α-<i>C</i>-Allyl Carboxylic Acids
作者:Taiki Fujita、Tomohiro Yamamoto、Yuya Morita、Hongyu Chen、Yohei Shimizu、Motomu Kanai
DOI:10.1021/jacs.8b02783
日期:2018.5.9
We describe herein the asymmetric synthesis of α-allyl carboxylic acids containing an α-quaternary stereocenter by a chiral hybrid catalyst system comprising palladium and boron complexes. The reaction proceeded through palladium-catalyzed ionization of α,α-disubstituted O-allyl esters for the generation of chiral π-allyl palladium complex as an electrophile, boron-catalyzed enolization of the carboxylate
我们在本文中描述了通过包含钯和硼配合物的手性混合催化剂体系不对称合成含有 α-季铵立体中心的 α-烯丙基羧酸。该反应通过钯催化的 α,α-二取代 O-烯丙酯电离生成手性 π-烯丙基钯配合物作为亲电试剂,硼催化羧酸部分的烯醇化生成手性 α,α-二取代羧酸衍生的烯醇化物作为亲核试剂,以及由此产生的亲核试剂和亲电子试剂之间的对映选择性偶联。硼和钯催化剂的手性配体的适当组合至关重要。反应在羧酸基团的 α 位进行化学选择性。