RESUMEN
Asymmetric conjugate additions of phosphonates to trans-crotonophenone and chalcone derivatives using a diaminomethylenemalononitrile organocatalyst resulted in the generation of the corresponding chiral γ-ketophosphonates in high yields with excellent enantioselectivities (up to 95% ee). This report is the first successful example of asymmetric 1,4-additions of phosphonate to α,ß-unsaturated ketones using an organocatalyst.
RESUMEN
Asymmetric direct vinylogous aldol reactions of furan-2(5H)-one with aldehydes in the presence of a catalytic amount of novel squaramide-sulfonamide organocatalyst resulted in the corresponding addition products with high to excellent enantioselectivities. This is the first successful report illustrating an example of highly stereoselective reactions using a squaramide-sulfonamide organocatalyst.
RESUMEN
The use of diaminomethylenemalononitrile (DMM) organocatalyst to promote the challenging 1,2-hydrophosphonylation of simple ketones and enones, which are also called α,ß-unsaturated ketones, is proposed and validated. This reaction provided the corresponding chiral α-hydroxy phosphonates in high to excellent yields and with enantioselectivity up to 96% ee.