Jorgensen-Hayashi prolinol catalysts

In contrast to the plethora of methodologies showing stereoselective applications of the Jorgensen-Hayashi catalyst (Chapter 8), a few reports have addressed the catal3dic ability of prolinol carbon-ethers in asymmetric synthesis. These procedures focused on the employment of commercially available (5)- or (R)-2-metho3qmiethylpyrrolidine, a scaffold originally... 

Recently, Mayr and coworkers examined in detail the reactivity of catalysts (S )-34 and (S)-35d, comparing them to the Jorgensen-Hayashi-silylated (5)-a,a-diphenyl-prolinol 3a. While X-ray structures of the enamines deriving from (S)-34 and (S )-35d confirmed an almost perfect planarity of the enamine nitrogen, the high reactivity of catalyst (5)-35d was found to be due to a hyperconjugative interaction of ac si with 7i cn) increasing its Lewis basicity. ... 

Prolinol silyl ethers were introduced independently by Jorgensen and Hayashi in 2005 (Figure 8.1) and this catalyst type quickly became one of the privileged structures in the asymmetric organocatalysis. ... 

Mechanism After the first report of iminium activation by MacMillan et al. in 2000, many studies have been made in this area. Two of the most important famihes of catalysts are MacMillan s catalysts and the TMS O-protected diaryl substituted prolinols developed independently by Jorgensen and Hayashi in 2005. 

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