Cooperative, highly enantioselective phosphinothiourea catalysis of imine-allene [3 + 2] cycloadditions.
A new family of phosphinthiourea catalysts was developed for the highly enantioselective synthesis of 2-aryl-2,5-hydropyrroles via a [3 + 2] cycloaddition of an electron-deficient allene with aryl and heteroaryl diphenylphosphinoylimines. The presence of both H2O and Et3N as additives was found to be important for achieving optimal rates. Dual activation of both nucleophile and electrophile by the bifunctional catalyst is invoked to account for the observed high reactivity and enantioselectivity.
Fang
Yuan-Qing
YQ
Department of Chemistry and Chemical Biology, Harvard University, Massachusetts 02138, USA.
Jacobsen
Eric N
EN
D000466:Alkadienes / Q000737:chemistry*; D002384:Catalysis; D003500:Cyclization; D007097:Imines / Q000737:chemistry*; D008956:Models, Chemical; D010720:Phosphines / Q000737:chemistry*; D011728:Pyridones / Q000138:chemical synthesis*; D013237:Stereoisomerism; D013890:Thiourea / Q000031:analogs & derivatives*
D000466:Alkadienes; D007097:Imines; D010720:Phosphines; D011728:Pyridones; D013890:Thiourea