A New Phosphinothiourea Catalyst

Significance

A new chiral bifunctional thiourea catalyst is introduced. Organocatalyst 1, derived from trans-2-amino-1-(diphenylphosphino)-cyclohexane and alanine, catalyzes the [3+2] cyclo­addition of imine 2 and allene 3 to substituted
2-aryl-2,5-dihydropyrroles 4 in good to high yields (68-90% yield) and high enantiomeric ratios (er = 97:3 up to 99:1). Both enantiomers of the aminophosphine precursor of catalyst 1 are prepared on a multi-gram scale by classical resolution.