2-Trimethylsilyl-1,3-dithiane → [2-(5-[1,3]dithian-2-ylidenemethyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5-yl)-ethyl]-dimethylamine

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Reaction Steps

To a solution of 2-trimethylsilyl-1,3-dithiane (2.5 mL, 12.8 mmol) in 10 mL of THF stirred at −78° C. and maintained under a nitrogen atmosphere was added butyllithium (5.1 mL of a 2.5M solution in hexane; 12.8 mmol) dropwise. The mixture was stirred in the cold for 20 minutes and then treated with 5-(2-dimethylamino-ethyl)-10,11-dihydro-5H-dibenzo[a,d]cycloheptene-5-carbaldehyde (102), 3.1 g in 20 mL of THF; 10.6 mmol) added dropwise. The solution was stirred for 1.5 hours at −78° C., warmed to ambient temperature and stirred an additional 1.5 hours. The solution was diluted with ethyl ether and quenched with saturated aqueous ammonium chloride. The organic layer was washed with saturated aqueous ammonium chloride (1×), saturated aqueous sodium bicarbonate (1×), and brine (1×), dried the over sodium sulfate, filtered, and evaporated to dryness. The resulting oil was purified by chromatography on silica gel (95:5 of methylene chloride:methanol). The product fractions were evaporated to dryness to yield the title product as an oil.

Provenance & Evidence