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DOI: 10.1055/s-2006-926309
Diastereoselective Alkylation of Chiral Perhydro 1,3,2-Oxazabenzophosphorinane-2-oxides Derived from (-)-8-Amino Menthol
Publication History
Received
17 August 2005
Publication Date:
19 January 2006 (online)


Abstract
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.
Key words
alkylation - asymmetric synthesis - diastereoselective reactions - phosphonamidates - phosphonates