A Practical and Stereoselective Organocatalytic Alkylation of Aldehydes with Benzodithiolylium Tetrafluoroborate. Issue 10 (17th March 2014)

• Record Type: Journal Article
• Authors: Gualandi, Andrea; Mengozzi, Luca; Giacoboni, Jessica; Saulnier, Steve; Ciardi, Moira; Cozzi, Pier Giorgio
• Is Part Of: Chirality. Volume 26:Issue 10(2014:Oct.)
• Page Start: 607
• Page End: 613
• Publication Date: 2014-03-17
• Subjects: Chirality -- Periodicals; Pharmaceutical chemistry -- Periodicals; 541.22
• DOI: 10.1002/chir.22303
• Languages: English
• ISSNs: 0899-0042

Abstract

<abstract abstract-type="main"> <title>ABSTRACT</title> <p>Recently, the direct substitution of allylic, benzylic, and tertiary alcohols has been achieved via S<sub>N</sub>1‐type reactions with catalytic amounts of Brønsted or Lewis acids. When a new stereogenic center is formed most of these transformations produce the desired product as a racemate, as these reactions proceed through carbenium ions. The arsenal of activation modes available in organocatalysis can be used to set up suitable reaction conditions in which chiral nucleophiles (enamine <named-content content-type="reactionType" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink">catalysis</named-content>) or chiral electrophiles (iminium <named-content content-type="reactionType" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink">catalysis</named-content>, chiral counterion <named-content content-type="reactionType" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink">catalysis</named-content>) can easily be generated. Recently, we have used stabilized carbenium ions, directly available or obtained from the corresponding alcohols, in new organocatalytic <named-content content-type="reactionType" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink">stereoselective</named-content> S<sub>N</sub>1‐type reactions. The commercially available carbenium ion benzodithiolylium tetrafluoroborate <bold>1</bold> can be used for the straightforward organocatalytic <named-content content-type="reactionType" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink">stereoselective</named-content><named-content content-type="reactionType" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink">alkylation of aldehydes</named-content>. In this account we will illustrate the application of this methodology in the total synthesis of natural products and the preparation of valuable starting materials. <italic>Chirality 26:607–613, 2014</italic>. © 2014 Wiley Periodicals, Inc.</p> </abstract>