Chemoselective Luche-Type Reduction of α,β-Unsaturated Ketones by Magnesium Catalysis

Abstract

The chemoselective reduction of α,β-unsaturated ketones by use of an economic and readily available Mg catalyst has been developed. Excellent yields for a wide range of ketones have been achieved under mild reaction conditions, short times, and low catalyst loadings (0.2−0.5 mol %).

Molecular Main Group Metal Hydrides

“…Magre and Rueping have described that the chemoselective reduction of α,β-unsaturated and propargylic ketones may be achieved with HBpin through the use of a (0.2–0.5 mol %) n Bu 2 Mg pre-catalyst . Excellent yields (>95%) were obtained from conversion of a wide range of ketones to the corresponding alcohols under mild reaction conditions (room temperature, 2–5 h).…”

“…315 Magre and Rueping have described that the chemoselective reduction of α,β-unsaturated and propargylic ketones may be achieved with HBpin through the use of a (0.2−0.5 mol %) n Bu 2 Mg pre-catalyst. 316 Excellent yields (>95%) were obtained from conversion of a wide range of ketones to the corresponding alcohols under mild reaction conditions (room temperature, 2−5 h). A mechanism reminiscent of that initially suggested by Hill and coworkers was proposed, in which catalysis is initiated via the formation of an active n BuMgH species.…”

Recent developments in the reduction of unsaturated bonds by magnesium precursors

“…0.2–0.5 mol% of the catalyst aided chemoselective reduction of α , β ‐unsaturated ketones and excellent yields were achieved using pinacolborane under ambient conditions. [ 61 ] Besides, successful reduction of a number of enones and propargylic ketones were achieved. Scheme 11 sets forth the proposed mechanism for the formation of an active Mg‐H complex followed by the sequential catalytic cycle.…”

Reduction of Cyclic and Linear Organic Carbonates Using a Readily Available Magnesium Catalyst

“…Although magnesium is one of the most abundant metals on earth, the application of magnesium-based catalysts for organic reactions is still relatively unexplored compared with other metals. − Recently, magnesium complexes, such as β-diketiminato–magnesium complexes, , have been employed for the hydroboration of unsaturated polarized bonds, including aldehydes, ketones, and esters. − Our group reported a protocol for the selective hydroboration of terminal and internal alkynes catalyzed by commercially available MgBu 2 . Mechanistic studies revealed that in the presence of the reductant HBpin, an active BuMgH species is formed in situ .…”