Synthesis 2017; 49(02): 269-274
DOI: 10.1055/s-0036-1588367
paper
© Georg Thieme Verlag Stuttgart · New York

Catalytic Prins Reaction Effected by Molecular Iodine in the Presence­ of Bis(trifluoromethanesulfonyl)imide Salts

Wacharee Harnying*
Department of Chemistry (Organic Chemistry), University of Cologne, Greinstraße 4, 50939 Cologne, Germany   eMail: berkessel@uni-koeln.de
,
Jörg-M. Neudörfl
Department of Chemistry (Organic Chemistry), University of Cologne, Greinstraße 4, 50939 Cologne, Germany   eMail: berkessel@uni-koeln.de
,
Albrecht Berkessel*
Department of Chemistry (Organic Chemistry), University of Cologne, Greinstraße 4, 50939 Cologne, Germany   eMail: berkessel@uni-koeln.de
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Publikationsverlauf

Received: 03. November 2016

Accepted: 07. November 2016

Publikationsdatum:
09. Dezember 2016 (online)


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Dedicated to Prof. Dieter Enders on the occasion of his 70th birthday

Abstract

The Prins reaction is an efficient method for the direct generation of 1,3-dioxanes from alkenes and aldehydes. As first published in 2008, this process can be effected by stoichiometric amounts of molecular iodine. We herein report a catalytic protocol allowing the use of iodine at low loading (0.5–5 mol%), smoothly effecting the condensation of styrenes with aliphatic aldehydes to rac-1,3-dioxanes. Moreover, this mild catalytic system effects the isomerization of the 1,3-dioxane products to the thermodynamically favored one. As a result, substi­tuted rac-1,3-dioxanes were prepared in high yields (up to 92%), and with high diastereoselectivities (d.r. up to 82:18). For the application of iodine in catalytic amounts, the addition of pyridinium bis(trifluoromethanesulfonyl)imide (TFSI) salts in a 1:1 ratio to iodine is the key to success.

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