Copper‐Catalyzed Tandem Hydrocupration and Diastereo‐ and Enantioselective Borylalkyl Addition to Aldehydes

Abstract

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.

One-pot two-step chemoenzymatic deracemization of allylic alcohols using laccases and alcohol dehydrogenases

“…As a consequence, several chemical methodologies have been described to synthesize these compounds in a chiral fashion [6]. Recent examples involve the (stereoselective) formation of C-C bonds, such as the alkenylation of aldehydes [7], the coupling of alcohols and alkynes under redox neutral conditions [8], the aldol addition on α,β-unsaturated ketones [9], the alkyl addition on α,β-unsaturated aldehydes [10], and the Stille coupling reaction [11].…”