Stereoselective Mannich-type reaction of chiral aldimines with 2-silyloxybutadienes by using trifluoromethanesulfonic acid

Novel stereoselective Mannich-type reaction of chiral aldimines with 2-silyloxybutadienes in the presence of trifluoromethanesulfonic acid has been carried out to give the corresponding products, which are not obtained by general Lewis acid-promoted methods, with 70–92% de in 62–74% yield. No cycloadducts were detected in the crude product by 1H NMR.