Enantioenriched acid, ester, and ketone β-phenyl homoenolate synthetic equivalents from N-Boc- N-( p-methoxyphenyl)cinnamylamine

• Published in: Tetrahedron letters Vol. 41; no. 49; pp. 9527 - 9531
• Main Authors: Whisler, Marna C, Soli, Eric D, Beak, Peter
• Format: Journal Article
• Language: English
• Published: OXFORD Elsevier Ltd 02.12.2000; Elsevier
• Subjects: Chemistry; Chemistry, Organic; Physical Sciences; Science & Technology; HOMOALDOL REACTION; ENANTIOSELECTIVE LITHIATION; ASYMMETRIC-SYNTHESIS; LITHIATION-SUBSTITUTION SEQUENCES
• ISSN: 0040-4039; 1873-3581
• DOI: 10.1016/S0040-4039(00)01663-4

Oxidation of the β-substituted highly enantioenriched aldehydes obtained by hydrolysis of the 3,3-disubstituted enecarbamates affords enantioenriched β-substituted acids and esters. Lithiation of enantioenriched 3,3-disubstituted enecarbamates and subsequent reaction with electrophiles provides vinylically substituted enecarbamates. The use of benzyl and alkyl halide electrophiles affords α-substituted enecarbamates, which can be hydrolyzed to provide enantioenriched β-substituted ketones. Reaction of the lithiated intermediate with ketones affords oxazolidinones, which can be reductively ring-opened with DIBAL and hydrolyzed to provide enantioenriched β-substituted, α′-hydroxy ketones. These transformations demonstrate that the enantioselective lithiation of N-Boc- N-( p-methoxyphenyl)cinnamylamine provides a reactive intermediate which can be a ketone, acid, or ester homoenolate synthon.