We report the catalytic enantioselective conjugate addition of a borylalkyl copper nucleophile generated in situ from a 1,1-diborylmethane derivative to α,β-unsaturated diesters. In the presence of a chiral N-heterocyclic carbene (NHC)–copper catalyst, this method facilitated the enantioselective incorporation of a CH2Bpin moiety at the β-position of the diesters to yield β-chiral alkyl boronates in up to 86 % yield with high enantioselectivity. The alkylboron moiety in the resulting chiral diester products was converted into various functional groups by organic transformation of the C−B bond.
Bibliographical noteFunding Information:
This research was supported by National Research Foundation of Korea (NRF) grants (Nos.2019R1A2C2005706 and 2019R1A4A2001440) funded by the Korean government.
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- asymmetric catalysis
- conjugate addition