title: Catalytic asymmetric Petasis reactions of vinylboronates.
abstract: Binaphthol-catalyzed asymmetric Petasis reactions of salicylaldehydes with dibutyl vinylboronates and secondary amines in the presence of 4 Å molecular sieves (MS) afforded products with up to 99% ee in isolated yields of 39-94%. The 99% ee of the product indicated that the reaction by the binaphthol-catalyzed pathway was roughly 500 times faster than the uncatalyzed pathway. NMR experiments ((1)H and (11)B) showed that the amine component played a role in triggering the reaction between the binaphthol catalyst and the vinylboronate in the catalytic reaction sequence. The 4 Å MS enhanced both the rate and enantioselectivity by effective removal of water from the reaction system. A novel rearrangement reaction of the unconjugated allylic amine Petasis reaction product to a conjugated allylic amine was also observed.
authors: Chemical Process Research and Development, Biogen Idec , 14 Cambridge Center, Cambridge, Massachusetts 02142, United States.
authors: Xianglin
authors: X
authors: Shi
authors: William F
authors: WF
authors: Kiesman
authors: Anna
authors: A
authors: Levina
authors: Zhili
authors: Z
authors: Xin
mesh_terms: D000447:Aldehydes / Q000737:chemistry; D000588:Amines / Q000737:chemistry; D001897:Boronic Acids / Q000737:chemistry*; D002384:Catalysis; D015394:Molecular Structure; D009284:Naphthols / Q000737:chemistry*; D014753:Vinyl Compounds / Q000737:chemistry*
chemical_list: D000447:Aldehydes; D000588:Amines; D001897:Boronic Acids; D009284:Naphthols; D014753:Vinyl Compounds; C013243:salicylaldehyde