Diastereospecific synthesis of phosphinidene-capped cyclodextrins leading to introverted ligands

alpha-Cyclodextrins (alpha-CDs) containing PPh units which cap the primary face of the CD were obtained in high yield by reaction of Li2PPh with A,B- or A,C-dimesylated and A,B,D,E-tetra-mesylated precursors; the resulting phosphines are diastereomerically pure and constitute valuable precursors for the synthesis of metallo-cavitands.