Tri-tert-butylphosphine tetrafluoroborate → methyl 7-[2-((Z)-3-diethylaminoprop-1-enyl)-4-fluorobenzenesulfonyl-amino]-10H-9-oxa-1,2-diazaphenanthrene-8-carboxylate

Participants

Reaction Conditions

Reaction Steps

A mixture of methyl 7-(2-bromo-4-fluorobenzenesulfonylamino)-10H-9-oxa-1,2-diazaphenanthrene-8-carboxylate (Intermediate 5, 0.403 g), N,N-diethyl-N—((Z)-1-tributylstannanylprop-1-en-3-yl)-amine (Intermediate 2, 0.656 g), tris(dibenzylidene-acetone)dipalladium(0) (0.037 g) and tri-tert-butylphosphonium tetrafluoroborate (0.024 g) in dioxan (10 mL) and DMSO (1 mL) was stirred and heated at 95° C. under nitrogen for 90 minutes. Further N,N-diethyl-N—((Z)-1-tributylstannanylprop-1-en-3-yl)-amine (Intermediate 2, 0.656 g), tris(dibenzylideneacetone)dipalladium(0) (0.037 g) and tri-tert-butylphosphonium tetrafluoroborate (0.024 g) were added and the mixture was heated at 95° C. under nitrogen for a further 45 minutes. After cooling, the mixture was diluted with ethyl acetate and washed three times with water. The combined aqueous extracts were extracted with DCM and the combined organic layers were filtered through a phase separator. The filtrate was evaporated in vacuo and the residue was purified by chromatography on silica, eluting with a mixture of methanol and DCM with a gradient of 0-20% to give methyl 7-[2-((Z)-3-diethylaminoprop-1-enyl)-4-fluorobenzenesulfonylamino]-10H-9-oxa-1,2-diazaphenanthrene-8-carboxylate (0.253 g) as a sandy coloured solid.

Provenance & Evidence