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Hydrophosphination of propargylic alcohols and amines with phosphine boranes
Carl A Busacca1, Bo Qu, Elisa Farber
1Chemical Development, Boehringer-Ingelheim Pharmaceuticals, Inc., 900 Ridgebury Road, Ridgefield, Connecticut 06877, USA. carl.busacca@boehringer-ingelheim.com
Abstract:
The first uncatalyzed hydrophosphinations of propargylic amines and alcohols with phosphine- borane complexes are described. The reactions proceed at ambient temperature or below without the use of protecting groups or the need to handle pyrophoric secondary phosphines, furnishing air-stable phosphineborane-amines and alcohols in good yields. Utilization of chiral propargylic substrates and unsymmetrical secondary phosphineboranes leads to diastereomeric P-chiral products that can be separated by fractional crystallization or chromatography. Initial applications of these new P-X species to asymmetric catalysis are detailed.
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