With the aid of chiral phosphoric acid, enantioselective 1,6-addition of tryptamines to in situ formed alkynyl 7-methylene-7H-indoles from tertiary α-(7-indolyl)methanols has been established, furnishing axially chiral tetrasubstituted allenes in high yields.
This review emphasizes on the recent advances on the synthesis of triarylmethanes using regio- and stereoselective approaches, aiming to engage readers in organic synthesis.
Chiral phosphoric acid catalysts (CPA), as important organic catalysts, exhibit excellent catalytic efficiency due to their bifunctional properties. From the perspective of catalyst design, this presents their development in recent years.
Chiral phosphoric acid catalyzed enantioselective synthesis of tetrasubstituted chiral allenes has been achieved via 1,12-addition of indole-2-carboxylates to alkynyl aza-biphenyl quinone methides formed in situ from α-functionalized alcohols.
Chiral phosphoric acid (CPA)-catalyzed Diels–Alder reaction between 2-trifluoroacetamido-1,3-dienes and α,β-unsaturated ketones has been theoretically investigated, and the reaction mechanism and origin of the enantioselectivity were uncovered.