Benzophenone imine → (S)-tert-butyl 2-(4-(diphenylmethyleneamino)phenyl)morpholine-4-carboxylate

Participants

Reaction Conditions

Reaction Steps

(S)-tert-Butyl 2-(4-bromophenyl)morpholine-4-carboxylate (47 g, 137 mmol), diphenylmethanimine (29.9 g, 27.6 m, 165 mmol), BINAP (6.41 g, 10.3 mmol) and Pd2(dba)3 (3.14 g, 3.43 mmol) were dissolved under argon in dry and de-aerated toluene (940 ml) and treated with sodium tert-butoxide (18.5 g, 192 mmol). The dark brown mixture was stirred at 90° C. for 18 h. The yellow/brown reaction mixture was diluted with toluene (700 ml), cooled to rt and extracted twice with water. The organic layer was separated, dried over magnesium sulfate and concentrated in vacuo. The crude product was diluted with 300 ml hexane, stirred for 1 h and filtered off, leading to an orange solid (68 g) which was purified by column chromatography (1.3 kg silicagel, 20% ethylacetate/heptane). The combined and concentrated fractions were suspended in hexane, stirred for 17 h, filtered off and dried under high vacuum, to yield 54.1 g (89%) yellow solid. MS (ISP): 443.3 ([M+H]+).

Provenance & Evidence