Intramolecular [2+ 2] cycloadditions of ketenes to carbonyl groups. A novel synthesis of substituted benzofurans

WT Brady, YSF Giang, AP Marchand…

Index: Brady, William T.; Giang, Yun-seng F.; Marchand, Alan P.; Wu, An-hsiang Journal of Organic Chemistry, 1987 , vol. 52, # 15 p. 3457 - 3461

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Citation Number: 39

Abstract

Method B. Compound 3a (500 mg, 1.44 mmol) and sodium chloride (300 mg, excess) were suspended in dimethyl sulfoxide (DMSO, 30 mL). The reaction mixture was heated at 150" C for 1.5 h; slight darkening of the reaction mixture occurred, and a gas was evolved slowly during this period. The reaction mixture was then cooled to room temperature and water (150 mL) was added. The resulting mixture was extracted with methylene chloride (3 X 25 ...