Ab initio and density functional calculations on the pericyclic vs pseudopericyclic mode of conjugated nitrile ylide 1,5-electrocyclizations / Fabian WMF,Kappe CO,Bakulev VA // JOURNAL OF ORGANIC CHEMISTRY. - 2000. - V. 65, l. 1. - P. 47-53.

ISSN/EISSN:

0022-3263 / нет данных

Type:

Article

Abstract:

Ab initio (MP2/6-311+G{*}{*} and MP4(SDTQ)/6-311+G{*}{*}//MP2/6-311+G{*}{*}) and density functional (B3LYP/6-311+G{*}{*}) calculations on the ring closure reactions of conjugated nitrile ylides 1a-e, 3, and 6 to the corresponding oxazoles 2a, 5, 7, and 8; thiazoles 2b and 4; imidazole 2c; and pyrroles 2d and 2e, respectively, are reported. Vinyl nitrile ylides Id and le cyclize with a substantially higher barrier than nitrile ylides containing a heteroatom Geometric features as well as electronic structures as obtained by NBO analysis are indicative of a pericyclic, monorotatory 1,5-electrocyclization of Id and le. For nitrile ylides where X = heteroatom, a pseudopericyclic heteroelectrocyclization pathway, characterized by in-plane attack of the heteroatom's lone pair at the nitrile ylide group, is found. For 3 and 6, where two different cyclization products are possible, the calculated barriers and reaction energies are in line with the experimentally observed direction of reaction. Vinyl nitrile ylides Id and le are characterized by an allene, acyl substituted derivatives la, Ib, 3, and 6 by a propargyl type structure. The nitrogen derivative Ic represents an intermediate case.

Author keywords:

ALPHA-DIAZOCARBONYL COMPOUNDS; 1,3-DIPOLAR CYCLOADDITIONS; TRANSITION STRUCTURES; AROMATICITY; REACTIVITY; GENERATION; HETEROCYCLIZATION; ISOMERIZATION; REARRANGEMENT; FORMYLKETENE

DOI:

10.1021/jo990997s

Web of Science ID:

ISI:000084816300008

Соавторы в МНС:

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Другие поля

Поле	Значение
Month	JAN 14
Publisher	AMER CHEMICAL SOC
Address	1155 16TH ST, NW, WASHINGTON, DC 20036 USA
Language	English
Keywords-Plus	ALPHA-DIAZOCARBONYL COMPOUNDS; 1,3-DIPOLAR CYCLOADDITIONS; TRANSITION STRUCTURES; AROMATICITY; REACTIVITY; GENERATION; HETEROCYCLIZATION; ISOMERIZATION; REARRANGEMENT; FORMYLKETENE
Research-Areas	Chemistry
Web-of-Science-Categories	Chemistry, Organic
ResearcherID-Numbers	Kappe, C. Oliver/C-9771-2011
ORCID-Numbers	Kappe, C. Oliver/0000-0003-2983-6007
Number-of-Cited-References	70
Usage-Count-Last-180-days	1
Usage-Count-Since-2013	14
Journal-ISO	J. Org. Chem.
Doc-Delivery-Number	275JD