Totally diastereoselective synthesis of new P-chirogenic o-trimethylsiloxyaryl diazaphospholidines and o-hydroxyaryl diazaphospholidine–borane complexes

• Published in: Journal of organometallic chemistry Vol. 643; pp. 237 - 246
• Main Authors: Ngono, Christian J, Constantieux, Thierry, Buono, Gérard
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-02-2002
• Subjects: Bidentate PO ligands; Hemilabile ligands; Intramolecular 1,3-carbanionic rearrangement; P-stereogenic o-phosphinophenols; Phosphine–borane complexes; P-stereogenic o-phosphinophenols; Intramolecular 1,3-carbanionic rearrangement; Bidentate PO ligands; Phosphine–borane complexes; Hemilabile ligands
• ISSN: 0022-328X; 1872-8561
• DOI: 10.1016/S0022-328X(01)01314-6

The totally diastereoselective synthesis of several P(III)-chirogenic
o-trimethylsiloxyaryl diazaphospholidines
4 was achieved by exchange reactions in refluxing toluene from the key intermediates,
o-trimethylsiloxyaryl bis(dimethylamino) phosphines
2, and various chiral diamines
3. In the case of the use of a non-
C
2-symmetric chiral auxiliary such as (
S)-2-anilinomethylpyrrolidine (
3a), compounds
4a–
g, containing a stereogenic phosphorus atom, were obtained in diastereomerically pure form as the thermodynamic
anti-diastereomers. Complexation of the diazaphospholidines
4 by borane-dimethylsulfide and subsequent methanolysis of the siloxy ether function lead to the formation of the desired
o-hydroxyaryl diazaphospholidine-borane complexes
5 in good yields, ranging from 71 to 86%.
Totally diastereoselective synthesis of several P(III)-chirogenic
o-trimethylsiloxyaryl diazaphospholidines was achieved from various substituted
o-bromophenols
1a–
g and chiral diamines. Complexation of the diazaphospholidines by borane-dimethylsulfide and subsequent methanolysis of the siloxy ether function led to the formation of the desired
o-hydroxyaryl diazaphospholidine-borane complexes
5a–
j in good yields, ranging from 38 to 86%.