Chalcogeno Morita−Baylis−Hillman Reaction of 2‐(Methylchalcogeno)phenyl Vinyl Ketones with Aldehydes, Ketones, and α‐Dicarbonyl Compounds

Abstract

AbstractReactions of 2‐(methylchalcogeno)phenyl vinyl ketones 1 and 4 with aldehydes 5 were conducted in the presence of BF3·Et2O. The reaction was quenched by addition of Et3N and gave the Morita−Baylis−Hillman adducts 6−7 in good yields. When the reaction mixture of 1 with 5a was worked up with saturated aqueous NaHCO3, the sulfonium salt 8a was obtained together with 6. Ketones 10, α‐diketones, and α‐oxo esters 13, which hardly react in the traditional Morita−Baylis−Hillman reaction, similarly reacted with 2‐(methylchalcogeno)phenyl vinyl ketones 1 and 4 to give the Morita−Baylis−Hillman adducts 11−12 and 14−15. Selenochromanones 9 and 16 were obtained together with 7 and 15 from reactions of seleno derivative 4, with 5 and 13 as by‐products. The formation mechanism for the sulfonium salt syn‐trans‐8a is discussed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)