Cope Elimination Flipbook PDF

Cope Elimination

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Compiled by: Prateek Khanna

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COPE ELIMINATION vi

"I wish to heat the Sun"

BY PRATEEK KHANNA

GENERAL REACTION

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Compiled by: Prateek Khanna

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The Cope Reaction of N-oxides, which can easily be prepared in situ from tertiary amines with an oxidant such as peracid, leads to alkenes via a thermally induced synelimination in aprotic solvents.

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"I wish to heat the Sun"

MECHANISM OF REACTION

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Compiled by: Prateek Khanna

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The Cope Elimination is a syn periplanar elimination in which six electrons move in a fivemembered ring according to a concerted, thermally-induced mechanism to yield an alkene and a hydroxylamine:

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"I wish to heat the Sun"

Compiled by: Prateek Khanna

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The sterically demanding amine oxide function reacts preferentially with the more easily accessible hydrogens, and often gives good selectivity favoring the less-substituted alkene. Thus, for simple alkenes, the reaction follows the Hofmann Rule.

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"I wish to heat the Sun"

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Compiled by: Prateek The following structures exemplify the stereochemical requirement forKhanna reaching a five-membered cyclic transition state and the influence of sterically demanding groups for some cyclic compounds:

vi

"I wish to heat the Sun"