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Please login or sign up for a free trial to access the full content. Asymmetric Michael Addition of tert-Butyl 2-(1-Naphthyl)-4,5-dihydrooxazole-4-carboxylate to Ethyl Acrylate

DOI: 10.1055/sos-SD-205-00387

Shirakawa, S.; Maruoka, K.Science of Synthesis: Asymmetric Organocatalysis, (20122576.

A highly enantioselective synthesis of a potent metabotropic receptor ligand, (S)-α-(hydroxymethyl)glutamic acid (77), has been accomplished by the catalytic Michael addition of the tert-butyl ester 75 to ethyl acrylate, using the phosphazene base 74 (BEMP) in dichloromethane at 60°C in the presence of the chiral quaternary ammonium salt (S,S)-3 (R1=3,4,5-F3C6H2). Acid hydrolysis of the resulting intermediate 76 gives the target (Scheme 34).[‌62‌]

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