This is the abstract of a presentation made by Phil Sass in the Sunday
evening Division of Inorganic Chemistry poster session at
the August 2001 National Meeting of the American Chemical Society in Chicago.
Preparation of Primary Alkylphosphines by a Phospha-Gabriel Route
Philip A. Sass, Jeffrey B. Johnson, Ryan C. Nelson, and Brian A. O'Brien,
Department of Chemistry, Gustavus Adolphus College, 800 West College Avenue,
Saint Peter, MN 56082, Fax: 507-933-7041, email@example.com, firstname.lastname@example.org
The classic Gabriel synthesis of primary amines through alkylation of
potassium phthalimide, followed by cleavage with hydrazine, has long been
known as the preferred method for preparation of primary amines from alkyl
halides. Here we describe a phosphorus analog of the Gabriel synthesis.
Alkylphthaloylphosphines [1,2-C6H4(CO)2P-R] or bisphthaloylphosphinoalkanes
[C6H4(CO)2P-(CH2)n-P(CO)2C6H4] are readily prepared by reaction of cesium
phthaloylphosphide [Cs+1,2-C6H4(CO)2P-] with alkyl halides. Cleavage of
the phthaloylphosphines by phenylhydrazine (or hydrazine) produces N-phenylphthalhydrazide
(or phthalhydrazide) and the corresponding primary alkylphosphine. The
reactions proceed rapidly and in good yield, and isolation of the products
is straightforward. Spectroscopic and chemical characterization of the
phthaloylphosphines and primary alkylphosphines, as well as details of
the synthetic procedures, will be presented.