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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
Author(s) -
Fujita Kahee,
Fujioka Toshihiro,
Shimada Hideaki,
Ohta Kazuko,
Yoshino Akitoshi,
Okabe Yuji,
Fukudome Makoto,
Yuan DeQi
Publication year - 2004
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200400162
Subject(s) - chemistry , epoxide , nucleophile , regioselectivity , intramolecular force , ring (chemistry) , cyclodextrin , stereochemistry , organic chemistry , catalysis
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 ‐diequatorial products and ensures an efficient construction of fused heterocycles within the cyclodextrin belt. In the case of 2 I ,3 I :2 II ,3 II ‐di‐ manno ‐epoxy‐β‐cyclodextrin, a tandem‐type reaction is initiated by the attack by the 3 VII ‐OH group at the 2 I ‐C position to generate a fused pentacycle. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)