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Stereospecific Synthesis of α‐ and β‐Hydroxyalkyl P‐Stereogenic Phosphine–Boranes and Functionalized Derivatives: Evidence of the PO Activation in the BH 3 ‐Mediated Reduction
Author(s) -
Lemouzy Sébastien,
Nguyen Duc Hanh,
Camy Valentine,
Jean Marion,
Gatineau David,
Giordano Laurent,
Naubron JeanValère,
Vanthuyne Nicolas,
Hérault Damien,
Buono Gérard
Publication year - 2015
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201502647
Subject(s) - enantiopure drug , boranes , stereocenter , phosphine , chemistry , stereospecificity , borane , combinatorial chemistry , stereochemistry , organic chemistry , catalysis , medicinal chemistry , enantioselective synthesis , boron
Access to hydroxy‐functionalized P‐chiral phosphine–boranes has become an important field in the synthesis of P‐stereogenic compounds used as ligands in asymmetric catalysis. A family of optically pure α and β‐hydroxyalkyl tertiary phosphine–boranes has been prepared by using a three‐step procedure from readily accessible enantiopure adamantylphosphinate, obtained by semi‐preparative HPLC on multigram scale. Firstly, a two‐step one‐pot transformation affords the enantiopure hydroxyalkyl tertiary phosphine oxides in good yields and enantioselectivities. The third step, BH 3 ‐mediated reduction, allows the formation of the desired phosphine–boranes with excellent stereospecifity. The mechanistic study of this reduction provides new evidence to elucidate the crucial role of the pendant hydroxy group and the subsequent activation of the PO bond by the boron atom.