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1,3-Dipolar Cycloadditions of alpha-Diazo Ketones Derived from N-Protected (S)-Proline with Aromatic and Cycloaliphatic Thioketones


Mloston, Grzegorz; Pipiak, Paulina; Linden, Anthony; Heimgartner, Heinz (2015). 1,3-Dipolar Cycloadditions of alpha-Diazo Ketones Derived from N-Protected (S)-Proline with Aromatic and Cycloaliphatic Thioketones. Helvetica Chimica Acta, 98(2):190-200.

Abstract

Enantiomerically pure alpha-oxo diazo compounds derived from (S)-proline were used for 1,3-dipolar cycloaddition with aryl and hetaryl thioketones, as well as with cycloalkanethiones. Whereas the reactions with hetaryl thioketones in boiling THF yield alpha,beta-unsaturated ketones via a cascade of cycloaddition, 1,3-dipolar electrocyclization, and desulfurization, the analogous reactions with thiobenzophenone and cycloalkanethiones result in the formation of 1,3-oxathiole derivatives. In the latter case, the 1,5-dipolar electrocyclization of the intermediate thiocarbonyl ylide is the key step of the reaction sequence. In all cases, the isolated products are optically active, i.e., the multistep processes occur with retention of the stereogenic center incorporated via the use of (S)-proline as the precursor of the diazo compounds.

Abstract

Enantiomerically pure alpha-oxo diazo compounds derived from (S)-proline were used for 1,3-dipolar cycloaddition with aryl and hetaryl thioketones, as well as with cycloalkanethiones. Whereas the reactions with hetaryl thioketones in boiling THF yield alpha,beta-unsaturated ketones via a cascade of cycloaddition, 1,3-dipolar electrocyclization, and desulfurization, the analogous reactions with thiobenzophenone and cycloalkanethiones result in the formation of 1,3-oxathiole derivatives. In the latter case, the 1,5-dipolar electrocyclization of the intermediate thiocarbonyl ylide is the key step of the reaction sequence. In all cases, the isolated products are optically active, i.e., the multistep processes occur with retention of the stereogenic center incorporated via the use of (S)-proline as the precursor of the diazo compounds.

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Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Department of Chemistry
Dewey Decimal Classification:540 Chemistry
Language:English
Date:February 2015
Deposited On:12 Mar 2015 10:23
Last Modified:05 Apr 2016 19:07
Publisher:Wiley-Blackwell Publishing, Inc.
ISSN:0018-019X
Funders:National Science Center (PL-Cracow), (Grant Maestro-3; Dec-2012/06/A/ST5/00219)
Publisher DOI:https://doi.org/10.1002/hlca.201400334

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