N-(Diphenylmethylene)glycine tert-butyl ester → (2S)-tert-butyl 2-(diphenylmethyleneamino)-3-(6-o-tolylpyridin-3-yl)propanoate

Participants

Reaction Conditions

Reaction Steps

To a stirred mixture of 800 mg (2.33 mmol) of 5-(bromomethyl)-2-o-tolylpyridine hydrobromide, 689 mg (2.33 mmol, 1.0 equivalent) of tert-butyl 2-(diphenylmethyleneamino)acetate and 141 mg (0.233 mmol, 0.1 equivalent) of O-allyl-N-(9-anthracenylmethyl)cinchonidinium bromide in 14 mL of dichloromethane at −78° C. under argon was added 1.687 mL (5.83 mmol, 2.5 eq) of 2-t-butylimino-2-diethylamino-1,3-dimethyl-perhydro-1,3,2-diazaphosphorine over 5 min. The reaction mixture was stirred at −78° C. for 10 h and then allowed to warm to room temperature in situ. The mixture was directly purified by silica gel chromatography using ethyl acetate/dichloro-methane (1:4) as eluant (5×10 cm column), to give tan oil, 1.10 g, 100% yield.

Provenance & Evidence