Other Iminium Ion-Involved Cascade Reaction

2 Other Iminium Ion-Involved Cascade Reaction With the success of intramolecular addition of indoles to iminium ions in Pictet-Spengler reaction. 

R = electron-donating group, additive = 2 equiv TMSQ and 8 mol% H2O R = electron-withdrawing group, additive = 10 mol% BCI3 

Recently, the same group reported a highly enantioselective acylation of silyl ketene acetals 298 with acyl fluorides 299 via thiourea and a 4-pyrrolidinopyildine 

SCHEME 2.81 Chiral thiourea-catalyzed asymmetric polycyclization of hydroxy lactams. 

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