Chiral Conjoined Cavitands

Abstract

Tetrabromocavitand bowls are converted into rim-connected hexabromodimers in one step in 17–22% yields by oxidative coupling of higher order arylcuprates. ¹H NMR and single crystal X-ray analyses of the rim-connected dimers reveal a conformationally restricted structure in which the rims of the two cavitand bowls describe planes angled at 78.8° to one another. Each of the two bowl cavities are occupied by a guest, in addition to being partially occluded by a portion of the complementary bowl rim. These new host compounds exhibit a very unusual form of enantioisomerism.