STEREOSELECTIVE REACTIONS OF CHIRAL AMINES WITH RACEMIC CHLOROPHOSPHINES

Abstract

Racemic chlorophosphines react stereoselectively with chiral l-phenylethylamines or amino acid esters to give diastereomerically enriched aminophosphines 3, which were isolated as diastereomerically pure crystalline borane complexes. Oxidation, thionation, the reaction with methyl iodide provide optically active derivatives of aminophosphines. (R,S)- and (S,S)-stereomers of phosphinic acid amides were separated by crystallization and a flash-chromatography. The stereochemical properties of phosphorus acid amides were investigated. The mechanism of asymmetric induction at the trivalent phosphorus atom was rationalized.

Keywords:

• Asymmetric induction
• chiral aminophosphines
• stereoselectivity

Financial support of this work from the State Foundation of Basic Research of the Ukraine (Project 03.07/00047) is gratefully acknowledged.

Notes

^a The diastereomeric ratio was obtained by the ³¹P NMR method as average value of 2–3 measurements; PEA = 1-methylbenzylamine; DBU = diazabicycloundecene, DABCO = diazabicyclooctane.