Phenyltrimethylammonium bromide dibromide → 2-Bromo-1-((1as,5ar)-1,1,2-trimethyl-1,1a,5,5a-tetrahydro-3-thia-cyclopropa[a]pentalen-4-yl)-ethanone

Participants

Reaction Steps

To a solution of (1aS,5aR)-1-(1,1,2-trimethyl-1,1a,5,5a-tetrahydro-3-thia-cyclopropa[a]pentalen-4-yl)-ethanone (275 mg, 1.25 mmol) in DCM (7 mL) and methanol (3.5 mL) is added phenyltrimethyl-ammoniumbromid-dibromid (570 mg, 1.5 mmol) and the reaction mixture is stirred at rt for 30 min. Another portion of phenyltrimethyl-ammoniumbromid-dibromid (600 mg, 1.6 mmol) is added and stirring is continued for 1 h before the mixture is diluted with sat. aq. NaHCO3 (5 mL) and water (25 mL) and extracted twice with DCM (2×20 mL). The organic extracts are dried over Na2SO4 and evaporated to give crude 2-bromo-1-((1aS,5aR)-1,1,2-trimethyl-1,1a,5,5a-tetrahydro-3-thia-cyclopropa[a]pentalen-4-yl)-ethanone (250 mg) as a brownish oil; LC-MS: tR=1.06 min, [M+3]+=300.99.

Provenance & Evidence