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Branched-Selective Direct ?-Alkylation of Cyclic Ketones with Simple Alkenes.

ABSTRACT: Herein, we describe an intermolecular direct branched-selective ?-alkylation of cyclic ketones with simple alkenes as the alkylation agents. Through an enamine-transition metal cooperative catalysis mode, the ?-alkylation is realized in an atom- and step-economic manner with excellent branched selectivity for preparing ?-branched ketones. Employment of a pair of bulky Brønsted acid and base as additives is responsible for enhanced efficiency. Promising enantioselectivity (74?%?ee) has been obtained. Experimental and computational mechanistic studies suggest that a pathway through alkene migratory insertion into the Ir-C bond followed by C-H reductive elimination is involved for the high branched selectivity.

SUBMITTER: Xing D

PROVIDER: S-EPMC6604859 | biostudies-literature | 2019 Mar

REPOSITORIES: biostudies-literature

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Branched-Selective Direct α-Alkylation of Cyclic Ketones with Simple Alkenes.

Xing Dong D Qi Xiaotian X Marchant Daniel D Liu Peng P Dong Guangbin G

Angewandte Chemie (International ed. in English) 20190221 13

Herein, we describe an intermolecular direct branched-selective α-alkylation of cyclic ketones with simple alkenes as the alkylation agents. Through an enamine-transition metal cooperative catalysis mode, the α-alkylation is realized in an atom- and step-economic manner with excellent branched selectivity for preparing β-branched ketones. Employment of a pair of bulky Brønsted acid and base as additives is responsible for enhanced efficiency. Promising enantioselectivity (74 % ee) has been obtai ...[more]

PMID: 30707491

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