Beilstein J. Org. Chem.2019,15, 1304–1312, doi:10.3762/bjoc.15.129
of a highly active carbocation Lewis acid catalyst. The stereocontrol potential of the chiral tritylium ion pair was demonstrated by its application in an enantioselective Diels–Alder reaction of anthracene.
Keywords: anthracene; carbocationcatalysis; Diels–Alder reaction; Fe(III)-based phosphate
, the enantioselectivity was low in most cases. In addition, the synthetic efforts to access these chiral cations were generally non-trivial which limited their further development. Recently, we developed a chiral ion-pair strategy for asymmetric carbocationcatalysis, with chiral trityl phosphate as
(Scheme 1b). In our further explorations, we noticed that the dissociation of trityl phosphate was generally sluggish, thus limiting its applicability. To expand its utility, we report herein a metal-complexed phosphate anion for chiral carbocationcatalysis.
Weakly coordinating anions [22][23] have been