Kinetic and theoretical study of 4-exo ring closures of carbamoyl radicals onto C=C and C=N bonds

John Christopher Walton; G. A. DiLabio; E. S. Scanlan

doi:10.1021/ol047716+

Kinetic and theoretical study of 4-exo ring closures of carbamoyl radicals onto C=C and C=N bonds

John Christopher Walton, G. A. DiLabio, E. S. Scanlan

Research output: Contribution to journal › Article › peer-review

29 Citations (Scopus)

Abstract

Carbamoyl radicals were generated from oxime oxalate amides, and the kinetics of their 4-exo cyclizations onto C=C and C=NO bonds, leading to,beta-lactam-containing species, were studied by EPR spectroscopy. DFT computations with model carbamoyl radicals predicted 4-exo ring closures onto C=NO bonds to be facile, especially when tert-butyl substituents were present. The reverse ring-opening reactions were predicted to have much higher activation energies. Experimental evidence also favored slow reverse ring opening.

Original language	English
Pages (from-to)	155-158
Number of pages	4
Journal	Organic Letters
Volume	7
Issue number	1
DOIs	https://doi.org/10.1021/ol047716+
Publication status	Published - 6 Jan 2005

Keywords

ELECTRON-SPIN-RESONANCE
BETA-LACTAMS
GAMMA-LACTAMS
PARAMAGNETIC RESONANCE
CYCLIZATIONS
CYCLOBUTYLMETHYL
CHEMISTRY
AMIDES

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title = "Kinetic and theoretical study of 4-exo ring closures of carbamoyl radicals onto C=C and C=N bonds",

abstract = "Carbamoyl radicals were generated from oxime oxalate amides, and the kinetics of their 4-exo cyclizations onto C=C and C=NO bonds, leading to,beta-lactam-containing species, were studied by EPR spectroscopy. DFT computations with model carbamoyl radicals predicted 4-exo ring closures onto C=NO bonds to be facile, especially when tert-butyl substituents were present. The reverse ring-opening reactions were predicted to have much higher activation energies. Experimental evidence also favored slow reverse ring opening.",

keywords = "ELECTRON-SPIN-RESONANCE, BETA-LACTAMS, GAMMA-LACTAMS, PARAMAGNETIC RESONANCE, CYCLIZATIONS, CYCLOBUTYLMETHYL, CHEMISTRY, AMIDES",

author = "Walton, {John Christopher} and DiLabio, {G. A.} and Scanlan, {E. S.}",

year = "2005",

month = jan,

day = "6",

doi = "10.1021/ol047716+",

language = "English",

volume = "7",

pages = "155--158",

journal = "Organic Letters",

issn = "1523-7060",

publisher = "American Chemical Society (ACS)",

number = "1",

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TY - JOUR

T1 - Kinetic and theoretical study of 4-exo ring closures of carbamoyl radicals onto C=C and C=N bonds

AU - Walton, John Christopher

AU - DiLabio, G. A.

AU - Scanlan, E. S.

PY - 2005/1/6

Y1 - 2005/1/6

N2 - Carbamoyl radicals were generated from oxime oxalate amides, and the kinetics of their 4-exo cyclizations onto C=C and C=NO bonds, leading to,beta-lactam-containing species, were studied by EPR spectroscopy. DFT computations with model carbamoyl radicals predicted 4-exo ring closures onto C=NO bonds to be facile, especially when tert-butyl substituents were present. The reverse ring-opening reactions were predicted to have much higher activation energies. Experimental evidence also favored slow reverse ring opening.

AB - Carbamoyl radicals were generated from oxime oxalate amides, and the kinetics of their 4-exo cyclizations onto C=C and C=NO bonds, leading to,beta-lactam-containing species, were studied by EPR spectroscopy. DFT computations with model carbamoyl radicals predicted 4-exo ring closures onto C=NO bonds to be facile, especially when tert-butyl substituents were present. The reverse ring-opening reactions were predicted to have much higher activation energies. Experimental evidence also favored slow reverse ring opening.

KW - ELECTRON-SPIN-RESONANCE

KW - BETA-LACTAMS

KW - GAMMA-LACTAMS

KW - PARAMAGNETIC RESONANCE

KW - CYCLIZATIONS

KW - CYCLOBUTYLMETHYL

KW - CHEMISTRY

KW - AMIDES

UR - http://www.scopus.com/inward/record.url?scp=12344302496&partnerID=8YFLogxK

UR - http://pubs.acs.org/cgi-bin/abstract.cgi/orlef7/2005/7/i01/abs/ol047716+.html

U2 - 10.1021/ol047716+

DO - 10.1021/ol047716+

M3 - Article

SN - 1523-7060

VL - 7

SP - 155

EP - 158

JO - Organic Letters

JF - Organic Letters

IS - 1

ER -

Kinetic and theoretical study of 4-exo ring closures of carbamoyl radicals onto C=C and C=N bonds

Abstract

Keywords

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