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ALKENYL IMINIUM ION IN DIELS-ALDER REACTION: SYNTHESIS OF HIGHLY SUBSTITUTED N-HETEROCYCLES

Sarkar, Nihar Ranjan (2010) ALKENYL IMINIUM ION IN DIELS-ALDER REACTION: SYNTHESIS OF HIGHLY SUBSTITUTED N-HETEROCYCLES. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

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Abstract

Heterocyclic structures are critical components of an extensive collection of chemotherapeutic agents, either in service or under development, for treating numerous human illnesses. As a result, reaction technologies for heterocycle construction, in the context of both target- and diversity-oriented synthesis, enjoy a particularly prominent role in medicinal chemistry. Amongst all the C-C bond forming reactions, the classic Diels-Alder cycloaddition remains one of the most powerful transformations in organic chemistry especially for the formation of heterocyclic structures. Herein, we report a new methodology based on inverse electron demand Diels-Alder reaction utilizing reactive "N-alkenyl iminium ion" and a suitable dienophile for the stereoselective synthesis of substituted piperidine derivatives. In presence of a suitable Lewis acid, the "N-alkenyl iminium ion" is generated from the respective enamine-aminal derivative in situ and undergoes Diels-Alder reaction with a dienophile producing a highly substituted N-heterocycle (piperidine derivative) in one step.An efficient transition metal catalyzed isomerization technique for the synthesis of a new enamine-aminal synthon from respective N-allylamine derivatives has been developed. Cationic Ir-(COE) complex, a potential catalyst for ICR chemistry, was used for the isomerization of tosyl protected N-allylamine derivatives to synthesize N-tosyl-alkenyl iminium ion precursor in high geometrical selectivity and quantitative yield whereas carbamate (or amide) protected N-allylamine derivatives were isomerized with good E/Z ratio using Grubbs II.


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Details

Item Type: University of Pittsburgh ETD
Status: Unpublished
Creators/Authors:
CreatorsEmailPitt UsernameORCID
Sarkar, Nihar Ranjannrs17@pitt.eduNRS17
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee Chair Nelson, Scott G
Committee MemberDoemling, Alexander
Committee MemberWilcox, Craig
Committee Member Floreancig, Paul
Date: 28 January 2010
Date Type: Completion
Defense Date: 7 December 2009
Approval Date: 28 January 2010
Submission Date: 15 November 2009
Access Restriction: 5 year -- Restrict access to University of Pittsburgh for a period of 5 years.
Institution: University of Pittsburgh
Schools and Programs: Dietrich School of Arts and Sciences > Chemistry
Degree: PhD - Doctor of Philosophy
Thesis Type: Doctoral Dissertation
Refereed: Yes
Uncontrolled Keywords: N-HETEROCYCLES; ORGANIC SYNTHESIS; IMINIUM ION; PIPERIDINE
Other ID: http://etd.library.pitt.edu/ETD/available/etd-11152009-132705/, etd-11152009-132705
Date Deposited: 10 Nov 2011 20:04
Last Modified: 15 Nov 2016 13:51
URI: http://d-scholarship.pitt.edu/id/eprint/9680

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