Silica gel catalysed generation of episulfonium ions: a mild method for the synthesis of heterocycles
作者:Lorenzo Caggiano、David J. Fox、Stuart Warren
DOI:10.1039/b207542n
日期:2002.10.18
β-Carbonyloxy sulfides fragment when heated with silica or alumina to produce reactive episulfonium ion intermediates. Intramolecular activation of the leaving group and concurrent protection of a nitrogen or oxygen nucleophile via a cyclic carbamate or carbonate leads to the formation of pyrrolidines or cyclic ethers.
Rearrangement of a series of 1,n diols (n= 2 to 12), one OH group having an adjacent PhS group, under the two sets of conditions in the title, gives single compounds in high yield drawn from four possible classes of product. The effects of chain length help in our understanding of the mechanism of the rearrangements.
Scope and limitation of the [1,4] SPh shift in the synthesis of allylic alcohols
作者:Jason Eames、Maria A. de las Heras、Ray V.H. Jones、Stuart Warren
DOI:10.1016/0040-4039(95)02319-4
日期:1996.2
Rearrangement of 4-PhS-1,3-diols with TsCl in pyridine gives allylicalcohols. We discuss the scope and limitation of this reaction using structural variations, which help to elucidate the mechanism of the reaction. All reactions proceed in high yield and give synthetically useful products.