Does the wittig-still rearrangement proceed via a metal free carbanion?
作者:Birgit Kruse、Reinhard Brückner
DOI:10.1016/s0040-4039(00)97638-x
日期:1990.1
The steric course of [2,3] rearrangements of allyloxy methanides is almost not affected by the counterion (M = Li, Na, K, Rb, Cs) as demonstrated by the nearly metal independent E,Z and anti,syn selectivities of rearrangements 4 → 6 and 7 → 8, respectively.
The [2,3]-Wittig rearrangements of lithioalkyl allyl ethers exhibit different cis,trans-selectivities than [2,3] shifts in their lithiomethyl analogues
作者:Petra Keiner、Reinhard Brückner
DOI:10.1016/s0040-4020(01)89348-0
日期:1994.1
The reductive lithiation of O,S-acetals 9a-d initiated [2,3]-Wittig rearrangements whose cis,trans-selectivity depended on whether lithiomethyl (--> cis) or lithioalkyl allyl ethers reacted (--> trans). It is suggested that these rearrangements proceed via mixtures of the configurationally stable lithioether intermediates syn-13 and anti-13 and transition states 17(endo,exo) and 17(endo,endo), respectively.
KRUSE, BIRGIT;BRUCKNER, REINHARD, CHEM. BER., 122,(1989) N0, C. 2023-2025