Construction of a Fused Polycyclic Wall within the Cyclodextrin Belt To Ensure a Distorted Cavity: An Unusual trans‐Diequatorial Ring‐Opening Reaction of Cyclodextrin Epoxide Rings

Abstract

In the nucleophilic ring-opening reaction of 2 X ,3 X -manno-epoxides, the incoming nucleophiles attack the 3 X -C position of the epoxide almost exclusively. However, a quite unusual but very interesting reversed regioselectivity is observed when intramolecular hydroxy groups act as nucleophiles, that is, only the attack by 3 X−1 -OH at the 2 X -C position of the epoxide is observed. The reaction affords the apparent trans-di-

Selective modification of β-cyclodextrin: an unexpected tandem reaction enables the cross-linking of C2A and C2B via a sulfur atom

“…8 The bridging of two adjacent methylene carbons of a-CD and cross linking of the C3 x and C2 x+1 of b-CD by a single atom have been reported. 9 The present work represents the first example of bridging two neighboring C2 carbons by a single atom.…”