Efficient chiral <sup>1</sup>H NMR analysis of indoloquinazoline alkaloids phaitanthrin A, cephalanthrin-A and their analogues with a chiral phosphoric acid
A chiral phosphoric acid promoted enantioselective NMR recognition and determination of indoloquinazoline alkaloids phaitanthrin A, cephalanthrin-A and their analogues was described, which conveniently reveals their optical purities with high accuracy. Besides, pyrazine type tertiaryalcohols, cyclic amino alcohols and diamines can also be well resolved under optimal conditions. Importantly, this methodology