Universität zu Köln

Yatham, Veera Reddy ORCID: 0000-0002-3967-5342, Harrying, Wacharee, Kootz, Darius, Neudoerfl, Joerg-M., Schloerer, Nils E. and Berkessel, Albrecht ORCID: 0000-0003-0470-7428 (2016). 1,4-Bis-Dipp/Mes-1,2,4-Triazolylidenes: Carbene Catalysts That Efficiently Overcome Steric Hindrance in the Redox Esterification of alpha- and beta-Substituted alpha,beta-Enals. J. Am. Chem. Soc., 138 (8). S. 2670 - 2678. WASHINGTON: AMER CHEMICAL SOC. ISSN 0002-7863

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Abstract

As reported by Scheidt and Bode in 2005, sterically nonencumbered alpha,beta-enals are readily converted to saturated esters in the presence of alcohols and N-heterocyclic carbene catalysts, e.g., benzimidazolylidenes or triazolylidenes. However, substituents at the alpha- or beta-position of the alpha,beta-enal substrate are typically not tolerated, thus severely limiting the substrate spectrum. On the basis of our earlier mechanistic studies, a set of N-Mes- or N-Dipp-substituted 1,2,4-triazolium salts were synthesized and evaluated as (pre)catalysts in the redox esterification of various alpha- or beta-substituted enals. In particular the 1,4-bis-Mes/Dipp-1,2,4-triazolylidenes overcome the above limitations and efficiently catalyze the redox esterification of a whole series of alpha/beta-substituted enals hitherto not amenable to NHC-catalyzed transformations. The synthetic value of 1,4-bis-Mes/Dipp-1,2,4-triazolylidenes is further demonstrated by the one-step bicyclization of 10-oxocitral to (racemic) nepetalactone in diastereomerically pure form.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Yatham, Veera Reddy UNSPECIFIED orcid.org/0000-0002-3967-5342 UNSPECIFIED Harrying, Wacharee UNSPECIFIED UNSPECIFIED UNSPECIFIED Kootz, Darius UNSPECIFIED UNSPECIFIED UNSPECIFIED Neudoerfl, Joerg-M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Schloerer, Nils E. UNSPECIFIED UNSPECIFIED UNSPECIFIED Berkessel, Albrecht UNSPECIFIED orcid.org/0000-0003-0470-7428 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-281803
DOI:	10.1021/jacs.5b11796
Journal or Publication Title:	J. Am. Chem. Soc.
Volume:	138
Number:	8
Page Range:	S. 2670 - 2678
Date:	2016
Publisher:	AMER CHEMICAL SOC
Place of Publication:	WASHINGTON
ISSN:	0002-7863
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Chemistry > Institute of Organic Chemistry
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language N-HETEROCYCLIC CARBENE; DIELS-ALDER REACTIONS; TO-TAIL DIMERIZATION; ALPHA,BETA-UNSATURATED ALDEHYDES; GAMMA-BUTYROLACTONES; ENANTIOSELECTIVE SYNTHESIS; HOMOENOLATE EQUIVALENTS; ACTIVATED CARBOXYLATES; NUCLEOPHILIC CARBENE; STAUDINGER REACTION Multiple languages Chemistry, Multidisciplinary Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/28180