Cesium fluoride → (1-Methyl-8-thiophen-3-yl-1,2,3,4-tetrahydrobenzo [e][1,4]diazepin-5-ylidenemethyl)phosphonic acid diethyl ester

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Reaction Conditions

Reaction Steps

To 300 mg (0.77 mmol) of (8-bromo-1-methyl-1,2,3,4-tetrahydrobenzo[e][1,4]diazepin-5-ylidenemethyl)phosphonic acid diethyl ester (prepared as described in Example 41) in 2 ml of dioxane was added 116 mg (0.81 mmol) of thiophene-3-boronic acid, 8 mg (0.028 mmol) of tricyclohexylphosphine, 10.8 mg 0.012 mmol) of tris-(dibenzylideneacetone)-palladium (0) and 140 mg of caesium fluoride. The mixture was heated at 80° C. for 6 hours. The mixture was partitioned between ethyl acetate and water. The organic phase was evaporated and the product was purified by column chromatography (20 g IST pre-packed column) eluting with acetone—petroleum ether (40-60° C.) (1:3) to give 185 mg of (1-methyl-8-thiophen-3-yl-1,2,3,4-tetrahydrobenzo[e][1,4]diazepin-5-ylidenemethyl)phosphonic acid diethyl ester as a yellow gum; MS: m/e 393 [M+H]+.

Provenance & Evidence