Stereoselectivity in the addition of hydrogen chloride to cyclohex-1-enecarbonitrile: Possible role of chlorine lone pair-nitrile π-orbital pseudoallylic A1, 3 interaction

Balasubrahamanyam, SN and Balasubramanian, Madhusudhanan (1971) Stereoselectivity in the addition of hydrogen chloride to cyclohex-1-enecarbonitrile: Possible role of chlorine lone pair-nitrile π-orbital pseudoallylic A1, 3 interaction. In: Journal of the Chemical Society C: Organic Chemistry (5). pp. 827-830.

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Abstract

The (overall trans) addition of hydrogen chloride to cyclohex-1- enecarbonitrile in anhydrous alcoholic media proceeds to give cis-2-chlorocyclohexanecarboxylate (together with some cis-2- chlorocyclohexanecarboxamide): no corresponding products with the trans-configuration are detectable. In anhydrous ether the addition proceeds to give a single isomer, presumably cis-, of 2-chlorocyclohexanecarbonitrile, indicating that the configuration of the products may not be equilibrium-controlled in alcoholic media. An examination of the steric factors indicates that the transition state for protonation of the presumed intermediate, 2-chlorocyclohexylidenemethylideneimine, leading to cis-product is favoured if interaction between the lateral π-orbital of the C-N double bond and the lone-pairs on the chlorine atom at the 2-position is large. Consideration of interactions in the transition states meets Zimmerman's criticism that invoking A1, 3 interaction existing in ground states to explain product configuration takes insufficient account of the Curtin-Hammett principle.

Item Type:	Journal Article
Publication:	Journal of the Chemical Society C: Organic Chemistry
Publisher:	Royal Society of Chemistry
Additional Information:	Copyright of this article belongs to Royal Society of Chemistry.
Department/Centre:	Division of Chemical Sciences > Organic Chemistry
Date Deposited:	11 Jun 2010 08:36
Last Modified:	25 Feb 2019 09:24
URI:	http://eprints.iisc.ac.in/id/eprint/28326

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