Asymmetric synthesis of spirocyclic pyrrolidines and tetrahydrofurans by chiral aldol reactions and phenylthio migration
作者:Kelly Chibale、Stuart Warren
DOI:10.1016/0040-4039(91)80244-z
日期:1991.11
Highly enantioselective aldol reactions of the boron enolate of (S)-N-propionyl-4-(phenylmethyl)-2-oxazolidinone with α-phenylthio cycloalkanecarbaldehydes were achieved. Cyclisation of the chiral phenylthio sulphonamide and diols gave the title compounds in excellent yields and enantiomeric excess.
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.