Asymmetric Aza-MoritaBaylisHillman Reaction of N-Sulfonated Imines with Methyl Vinyl Ketone Catalyzed by Chiral Phosphine Lewis Bases Bearing Perfluoroalkanes as “Pony Tails”

✍ Scribed by Min Shi; Lian-Hui Chen; Wen-Dong Teng

• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: English
• Weight: 174 KB
• Volume: 347
• Category: Article
• ISSN: 1615-4150
• DOI: 10.1002/adsc.200505123

✦ Synopsis

Abstract

In the aza‐Morita–BaylisHillman reaction of N‐sulfonated imines (N‐arylmethylidene‐4‐methylbenzenesulfonamides and others) with methyl vinyl ketone (MVK), we found that in the presence of a catalytic amount of the chiral phosphine Lewis bases (R)‐(−)‐6,6′‐bis[tris(3,3,4,4,5,5,6,6,7,7,8,8,8‐tridecafluorooctyl)silyl]‐2′‐(diphenylphosphanyl)‐[1,1′]binaphthalenyl‐2‐ol LB2 and (R)‐(−)‐6,6′‐(3,3,4,4,5, 5,6,6,7,7,8,8,8‐tridecafluorooctyl) ‐2′‐(diphenylphosphanyl)‐[1,1′]binaphthalenyl‐2‐ol LB3 bearing two perfluoroalkane chains at 6,6′‐positions of the naphthalene framework, the corresponding adducts could be obtained in good yields with good to high ee (52–95% ee) at room temperature (15 °C) or low temperature (−20 °C) in THF, respectively. LB3 is more effective in this reaction than the previously reported original chiral phosphine Lewis base (R)‐(−)‐2′‐diphenylphosphanyl‐[1,1′]binaphthalenyl‐2‐ol LB1.