Recent development and improvement for boron hydride-based catalytic asymmetric reduction of unsymmetrical ketones

Abstract

Catalytic asymmetric reduction of prochiral ketones with hydrides such as boranes and borohydrides is one of the simplest and the most convenient methods for obtaining chiral alcohols. This tutorial review describes the most significant advances recently achieved for enhancing the enantioselectivity and practicability of the reduction using this methodology. The review covers the development of new homogeneous and/or immobilized catalysts for asymmetric reduction using borane or borohydride reagents and practical improvement of the well-known oxazaborolidine (OAB)-catalysed reduction through developing more stable, cost effective and recoverable OABs, scalable and environmental friendly borane sources, and one-pot procedures for the reduction.

Asymmetric Organocatalytic C‐C Bond Forming Reactions with Organoboron Compounds: A Mechanistic Survey

“…In addition, organoboron compounds have been widely used in asymmetric synthesiseither as reagentsor catalysts .…”

1‐Hydrosilatrane: A Locomotive for Efficient Ketone Reductions

“…The reduction of carbonyl groups is one of the most significant and well‐studied chemical transformations, which provides access to a plethora of products from simple starting materials . The development of chiral reducing agents has further given access to asymmetric products from prochiral ketones,[1a] including the crucially important, optically pure secondary alcohols …”

Synthesis of enantiomerically pure alcohols and amines via biocatalytic deracemisation methods

“…This predominance of chiral alcohol and amine moieties has stimulated the development of a multitude of synthetic and physicochemical approaches including chromatographic separation of racemates on high-performance porous chiral stationary phases, 8 enantioselective resolution using resolving agents 9 and stereoselective synthesis from ketones and imines. [10][11][12][13][14][15] Due to their inherent homochirality, enzymes play an important role as catalysts in the synthesis of optically active alcohols and amines. 16,17 Historically, hydrolase-catalysed kinetic resolution (KR, Scheme 1) reactions were the first ones to be explored.…”