Catalytic Asymmetric Addition of Thiols to Nitrosoalkenes Leading to Chiral Non-Racemic α-Sulfenyl Ketones

The first asymmetric organocatalytic sulfenylation of in situ derived nitrosoalkenes leading to chiral nonracemic α-sulfenylated ketones is described. The transformation proceeds in an umpolung fashion, relative to enolate/azaenolate methods, and uses simple thiols, thereby obviating the need for electrophilic sulfur reagents.