The Michael addition-alkylation process between gem-benzoyl-nitrostyrenes and 1,3-dicarbonyl compounds proceeded smoothly in the presence of a bifunctional squaramide, exclusively providing 2,3-dihydrofurans as trans-diastereomers in 33–92% isolated yields and excellent enantioselectivities (29–>99% ee).
宝石-苯甲酰基-硝基
苯乙烯和1,3-二羰基化合物之间的迈克尔加成烷基化过程在双官能方酰胺存在下顺利进行,仅提供
2,3-二氢呋喃为反式-非对映异构体,分离产率为33-92%,对映选择性优异(29%-> 99%ee)。