Diastereoselective Alkylation of Chiral Perhydro 1,3,2-Oxazabenzophosphorinane-2-oxides Derived from (-)-8-Amino Menthol
作者:Rafael Pedrosa、Beatriz López、Alicia Maestro
DOI:10.1055/s-2006-926309
日期:——
Chiral oxazaphosphorinanes, derived from (-)-8-amino menthol are alkylated with good to excellent diastereoselectivities. The regioselectivity in the alkylation is dependent on the base used for deprotonation. The ethyl oxazaphosphorinanes are alkylated at the nitrogen substituent after deprotonation with n-butyllithium, but in α-position to the phosphorous atom by deprotonation with LDA. On the contrary, the oxazaphosphorinanes with an alkyl substituent at the nitrogen atom or benzyl oxazaphosphorinane are alkylated in α-position to the phosphorous atom after deprotonation with either n-butyllithium or LDA.
The asymmetric synthesis of α-chloro α-alkyl and α-methyl α-alkyl phosphonic acids of high enantiomeric purity.
作者:Stephen Hanessian、Youssef L. Bennani、Daniel Delorme
DOI:10.1016/s0040-4039(00)97091-6
日期:1990.1
A method is described for the synthesis of α-chloro-α-alkyl- and α-methyl-α-alkylphosphonic acids in either enantiomeric form and in high optical purity, based on the asymmetric alkylation of α-substituted bicyclic phosphonamides derived from a C2 symmetrical diamine.