Synthesis 2007(19): 2987-2994  
DOI: 10.1055/s-2007-990777
PAPER
© Georg Thieme Verlag Stuttgart · New York

An Expedient Synthesis of Dialkylphosphane-Borane Complexes from Sodium Phosphide, and Their Alkylation under Phase-Transfer Conditions

Peter Kasák*, Michael Widhalm*
Institute for Organic Chemistry, University of Vienna, Währinger Straße 38, 1090 Vienna, Austria
Fax: +43(1)42779521; e-Mail: peter.kasak@savba.sk; e-Mail: m.widhalm@univie.ac.at;
Further Information

Publication History

Received 2 May 2007
Publication Date:
11 September 2007 (online)

Abstract

A group of seven achiral, α- and β-chiral dialkylphosphanes were synthesized in one step from sodium phosphide and alkyl sulfonates or sulfates. The corresponding borane complexes were further alkylated with alkyl, allyl, and benzyl bromides and mesylates to give tertiary mono- and diphosphanes, either via lithium phosphide-borane complexes at low temperature (45-78%) or under phase-transfer conditions (79-91%).

1

New address: P. Kasák, Polymer Institute of the Slovak Academy of Sciences, Dúbravská cesta 9, 84236 Bratislava, Slovakia.

14

A short communication on the synthesis of 5 and 6 and their use in the synthesis of C 3-symmetric trihydroxy trialkyl phosphane-borane complexes has been submitted recently: Kasák P.; Arion V.; Widhalm M. Tetrahedron Lett. 2007, 48, 5665.

18

The stoichiometry of the obtained material was not determined, but the empirical formula Na3P seems to be a reasonable assumption, since a 3:1 ratio of the reactants sodium and phosphorus afforded a homogeneous powder in high yield.