Nucleophilic Additions to Fused Bicyclic Five-Membered Ring Oxocarbenium Ions

Evidence for Preferential Attack on the Inside Face

Deborah M. Smith, Michelle B. Tran, Keith Woerpel

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Abstract

Evidence is provided that nucleophilic attack on five-membered ring oxocarbenium ions occurs from the inside face of the envelope. An eight-five fused-bicyclic system in which two substituents are constrained to pseudoequatorial positions underwent nucleophilic addition with selectivity that was comparable to an unconstrained monocyclic system. On the other hand, a bicyclic six-five analogue underwent reaction with low selectivity. This observation indicates that minimization of eclipsing interactions by attacking inside the envelope is not enough to control selectivity, but that the changes in the overall three-dimensional structure of the ring must be favorable as well. In the bicyclic six-five series, the six-membered ring is accommodated in the cation, but it destabilizes the transition state structure leading to the first-formed product of inside attack.

Original languageEnglish (US)
Pages (from-to)14149-14152
Number of pages4
JournalJournal of the American Chemical Society
Volume125
Issue number46
DOIs
StatePublished - Nov 19 2003

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Nucleophilic Additions to Fused Bicyclic Five-Membered Ring Oxocarbenium Ions : Evidence for Preferential Attack on the Inside Face. / Smith, Deborah M.; Tran, Michelle B.; Woerpel, Keith.

In: Journal of the American Chemical Society, Vol. 125, No. 46, 19.11.2003, p. 14149-14152.

Research output: Contribution to journalArticle

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