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A Substrate‐Based Approach to Skeletal Diversity from Dicobalt Hexacarbonyl ( C 1)‐Alkynyl Glycals by Exploiting Its Combined Ferrier–Nicholas Reactivity
Author(s) -
Lobo Fernando,
Gómez Ana M.,
Miranda Silvia,
López J. Cristóbal
Publication year - 2014
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201402149
Subject(s) - chemistry , propargyl , allylic rearrangement , glycal , nucleophile , reactivity (psychology) , intramolecular force , medicinal chemistry , ring (chemistry) , substituent , allene , stereochemistry , organic chemistry , catalysis , stereoselectivity , alternative medicine , medicine , pathology
Novel substrates that combine dicobalt hexacarbonyl propargyl (Nicholas) and pyranose‐derived allylic (Ferrier) cations have been generated by treatment of hexacarbonyldicobalt ( C ‐1)‐alkynyl glycals with BF 3 . Et 2 O. The study of these cations has resulted in the discovery of novel reaction pathways that have shown to be associated to the nature of O ‐6 substituent in the starting alkynyl glycals. Accordingly, compounds resulting from ring expansion (oxepanes), ring contraction (tetrahydrofurans), or branched pyranoses, by incorporation of nucleophiles, can be obtained from 6‐ O ‐benzyl, 6‐hydroxy, or 6‐ O ‐silyl derivatives, respectively. The use of a 6‐ O ‐allyl alkynyl glycal led to a suitable funtionalized oxepane able to experience an intramolecular Pauson–Khand cyclization leading to a single tricyclic derivative.