Stereocontrolled synthesis of E-homoallylic sulfides with 1,4,5 related chiral centres using the [2,3] sigmatropic rearrangement of sulfonium ylides
作者:Richard C. Hartley、Ian C. Richards、Stuart Warren
DOI:10.1039/p19960000359
日期:——
An aldol condensation sets up the stereochemistry. Lactonisation with 1,2 arylsulfanyl migration followed by reduction and sulfur-assisted dehydration converts the aldols stereospecifically into allylic sulfides with 1,2 related chiral centres. Sulfonium salts are generated from the allylic sulfides at low temperature, and are deprotonated to give sulfoniumylides which undergo [2,3] sigmatropic rearrangement
Stereochemical control in the synthesis of tetrahydrofurans by cyclisation of diols with phenylthio migration
作者:Varinder K. Aggarwal、Iain Coldham、Sara McIntyre、Francis H. Sansbury、María-Jesús Villa、Stuart Warren
DOI:10.1016/s0040-4039(00)80634-6
日期:1988.1
Cyclisation of diols with PhS migration leads to tetrahydrofurans by inversion at both the migration origin and terminus. Cyclisation to a secondary migration terminus is controlled by stereochemical factors.
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.