Aminophosphanes derived from chiral beta-aminoalcohols and carbonyliron complexes thereof

Phosphinites 2 and 4 derived from (-)-N-methylephedrine (1) and(+)-N-methyl -Psi-ephedrine (3), respectively are described. The synthesis of the chiral potassium hydridoferrate complex 8 from `N-methyl-diphenylephos' (2) and K HFe(CO)(4) was less selective than that of the previously described chiral zwitterionic hydride 7 from 'N,N-dimethyl-diphenylephosium' (6) and KHFe(CO )(4). Phosphines corresponding to deoxy derivatives of 'ephos' 2 and 'ephos ium' 6 were envisaged. A stereoselective conversion of 2 to the hydrohexafl uorophosphate of the N-methyl-diphenyldeoxyephos oxide isomer (5) is report ed, and an approach to the 'N,N-dimethyl-diphenyldeoxyephosium? (A) has bee n explored by stereoselective chlorination of the quaternary N,N-dimethylep hedrium (11). Likewise, 'N,N,N-trimethyl-diphenyldeoxyvalphosium' (B) was e nvisaged by chlorination of (+)-N,N,N-trimelhylvalinolium (14). In the pres ence of Ph2PLi, however, the chlorides 12a and 16 underwent elimination rea ctions instead of Cl- substitution, and the phosphines A and B did not form . In a reverse complexation-quaternization strategy, the 'N,N-dimethyl-diph enyldeoxyvalphos' - Fe(CO)(4) complex (20) has been selectively prepared an d subsequently converted to the corresponding ammonium complexes 21 and 20. HOTf. (C) 1999 Elsevier Science S.A. All rights reserved.