Asymmetric Aza‐MoritaBaylisHillman Reaction of N‐Sulfonated Imines with Methyl Vinyl Ketone Catalyzed by Chiral Phosphine Lewis Bases Bearing Perfluoroalkanes as “Pony Tails”

Abstract

In the aza-Morita-Baylis À 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)-(À)-6,6'-bis [tris(3,3,4,4,5,5,6,6,7,7,8,8,8- 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 8C) or low temperature ( À 20 8C) in THF, respectively. LB3 is more effective in this reaction than the previously reported original chiral phosphine Lewis base (R)-(À)-2'-diphenylphosphanyl-[1,1']binaphthalenyl-2-ol LB1.

The Morita-Baylis-Hillman Reaction: Insights into Asymmetry and Reaction Mechanisms by Electrospray Ionization Mass Spectrometry

“…In another work, Shi and coworkers synthesized the catalyst with an additional C 8 F 13 side-chain (ponytail, compound 29, Scheme 16 ). Testing catalyst 29 for MBH reaction, enantiomeric excesses reaching 90% chemical yield 90% and reaction times around 48 h were observed [ 31 ].…”

Aza‐Baylis–Hillman Reactions and Their Synthetic Applications

“…Scheme 36. The structure of the catalyst 31 was then modified through the introduction of two perfluoroalkane chains onto the naphthalene framework ( Figure 1); the corresponding adducts could be obtained in good yields and with good to excellent ee values. [45] Catalyst 34 was more effective in this reaction than the previously reported original chiral phosphane 1 (Scheme 37). Later on, we modified catalyst 31 to incorporate a series of multiple phenol groups and it was found that catalyst 35 gave the best asymmetric induction.…”

Privileged chiral catalysts in asymmetric Morita-Baylis-Hillman/aza-Morita-Baylis-Hillman reaction

“…Catalyst 36 was more efficient in the aza-MBH reaction of N-tosyl imines with methyl vinyl ketone than the previously reported original chiral phosphine 13 [57].…”