Benzophenone imine → (4R,9aR)-6-(Benzhydrylidene-amino)-4-methyl-3,4,9,9a-tetrahydro-1H-2,4a,5-triaza-fluorene-2-carboxylic acid tert-butyl ester

Participants

Reaction Steps

A mixture consisting of 0.20 g (0.54 mmol) (4R,9aR)-6-bromo-4-methyl-3,4,9,9a-tetrahydro-1H-2,4a,5-triaza-fluorene-2-carboxylic acid tert-butyl ester, 91 μl (0.54 mmol) benzophenone imine, 73.0 mg (0.76 mmol) sodium tert-butoxide, 5.6 mg (0.01 mmol) tris(dibenzylideneacetone)dipalladium chloroform complex and 10.1 mg (0.02 mmol) R-(+)-2,2′-bis(diphenylphosphino)-1,1′-binaphthalene in 3 ml toluene was stirred at reflux for 1 h. The reaction mixture was cooled to room temperature, poured into 10% aqueous sodium bicarbonate solution and extracted twice with ethyl acetate. The combined organic layers were washed with brine, dried over magnesium sulfate, filtered and evaporated. The residue was purified by chromatography on silica gel (0.032–0.063 mm) with n-hexane:ethyl acetate (2:1) as eluant to afford the product as a yellow foam (94.3%).

Provenance & Evidence