Boyer's Reaction and Transetherification: Mechanism and New Perspectives. Issue 4 (28th February 2016)

• Record Type: Journal Article
• Authors: Fraschetti, Caterina; Speranza, Maurizio; Guarcini, Laura; Roselli, Graziella; Filippi, Antonello
• Is Part Of: Chirality. Volume 28:Issue 4(2016)
• Page Start: 269
• Page End: 275
• Publication Date: 2016-02-28
• Subjects: ethers -- stereoselectivity -- bismuth bromide -- benzylation -- Lewis acid catalysis; Chirality -- Periodicals; Pharmaceutical chemistry -- Periodicals; 541.22
• DOI: 10.1002/chir.22581
• Languages: English
• ISSNs: 0899-0042

Abstract

Abstract: The progress and stereochemistry of Boyer's reaction were analyzed using several simple, chiral, alcoholic substrates, a variable amount of BiBr3 and different solvents. Basic solvents inhibit the reaction, while cyclohexane works very well; thus, it was our choice for the present study. In contrast to previous works, BiBr3 behaves as a true catalyst, being not consumed during the reaction. Although poisoning of the catalyst occurs to some extent, it does not prejudice the reaction yields (>90%). Gas chromatography/mass spectrometry (GC–MS) monitoring of the reaction revealed that, for example, in the presence of alcoholrac-1, isomeric ethers4 transetherificate to3 . We propose a unifying mechanistic model for both Boyer's andtransetherification reactions, in which the electronic properties of n‐adducts intermediates, formed by combination of bismuth(III) of BiBr3 and oxygen atoms of alcohols and ethers, play the key role for both the reactivity and the stereochemical outcome of the reaction. Chirality 28:269–275, 2016 . © 2016 Wiley Periodicals, Inc. Abstract :