We report the copper-catalyzed stereoselective addition of in situ generated chiral boron-α-alkyl intermediates to various aldehydes including α,β-unsaturated aldehydes under mild conditions. This tandem and multicomponent method facilitated the synthesis of enantiomerically enriched 1,2-hydroxyboronates bearing contiguous stereocenters in good yield with high diastereo- and enantioselectivity up to a ratio greater than 98:2. In particular, α,β-unsaturated aldehydes were successfully used as electrophiles in Cu−H catalysis through 1,2-addition without significant reduction. The resulting 1,2-hydroxyboronates were used in various transformations.
Bibliographical noteFunding Information:
This research was supported by National Research Foundation of Korea (NRF) grants (NRF-2016R1A2B4011719 and NRF-2016R1A4A1011451), funded by the Korean government (MEST).
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- aldehyde addition
- asymmetric catalysis
- enantioselective synthesis
- homogeneous catalysis