Synthesis 2006(5): 817-826  
DOI: 10.1055/s-2006-926309
PAPER
© Georg Thieme Verlag Stuttgart · New York

Diastereoselective Alkylation of Chiral Perhydro 1,3,2-Oxazabenzophos­phorinane-2-oxides Derived from (-)-8-Amino Menthol

Beatriz López, Alicia Maestro, Rafael Pedrosa*
Departamento de Química Orgánica, Facultad de Ciencias, Universidad de Valladolid, Dr. Mergelina s/n, 47011-Valladolid, Spain
Fax: +34(983)423211; e-Mail: pedrosa@qo.uva.es;
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Publikationsverlauf

Received 17 August 2005
Publikationsdatum:
19. Januar 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.