Chiral squaramide-catalyzed asymmetric synthesis of pyranones and pyranonaphthoquinones via cascade reactions of 1,3-dicarbonyls with Morita–Baylis–Hillman acetates of nitroalkenes
作者:Divya K. Nair、Rubem F. S. Menna-Barreto、Eufrânio N. da Silva Júnior、Shaikh M. Mobin、Irishi N. N. Namboothiri
DOI:10.1039/c4cc02279c
日期:——
Cascade reactions of 1,3-dicarbonyls with Morita-Baylis-Hillman acetates of nitroalkenes using a quinine derived chiral squaramide organocatalyst led to the formation of pyranones and pyranonaphthoquinones in good to excellent yields and high diastereo- and enantioselectivities. Representative examples of the reaction scale-up with a much lower catalyst loading without an appreciable loss of selectivities