In the presence of BiCl3–Zn(0), nearly equimolar amounts of allyl bromide reacted with carbonyl compounds containing a carboxyl group to afford the corresponding homoallylic alcohols having a carboxyl group or the intramolecular dehydrated lactones in good yields.
作者:Irem Yalavac、Sarah E. Lyons、Michael R. Webb、David J. Procter
DOI:10.1039/c4cc05404k
日期:——
5-exo/6-exo lactone radical cyclisation cascades deliver carbo[5.4.0]bicycles in a diastereoselective, one-pot process using SmI2 in the presence of H2O.
Lactone Radical Cyclizations and Cyclization Cascades Mediated by SmI<sub>2</sub>–H<sub>2</sub>O
作者:Dixit Parmar、Hiroshi Matsubara、Kieran Price、Malcolm Spain、David J. Procter
DOI:10.1021/ja3047975
日期:2012.8.1
Unsaturated lactones undergo reductive radicalcyclizations upon treatment with SmI(2)-H(2)O to give decorated cycloheptanes in a single highly selective operation during which up to three contiguous stereocenters are generated. Furthermore, cascade processes involving lactones bearing two alkenes, an alkene and an alkyne, or an allene and an alkene allow "one-pot" access to biologically significant
A general electron transfer reduction of lactones using SmI2–H2O
作者:Michal Szostak、Karl D. Collins、Neal J. Fazakerley、Malcolm Spain、David J. Procter
DOI:10.1039/c2ob00017b
日期:——
transfer reduction of lactones of all ring sizes and topologies using SmI2–H2O and a Lewis base to tune the redox properties of the complex. The current protocol permits instantaneous reduction of lactones to the corresponding diols in excellent yields, under mild reaction conditions and with useful chemoselectivity. We demonstrate the broad utility of this transformation through the reduction of complex
Ketyl-Type Radicals from Cyclic and Acyclic Esters are Stabilized by SmI<sub>2</sub>(H<sub>2</sub>O)<sub><i>n</i></sub>: The Role of SmI<sub>2</sub>(H<sub>2</sub>O)<sub><i>n</i></sub> in Post-Electron Transfer Steps
作者:Michal Szostak、Malcolm Spain、David J. Procter
DOI:10.1021/ja503494b
日期:2014.6.11
Mechanistic details pertaining to the SmI2-H2O-mediated reduction and reductive coupling of 6-membered lactones, the first class of simple unactivated carboxylic acid derivatives that had long been thought to lie outside the reducing range of SmI2, have been elucidated. Our results provide new experimental evidence that water enables the productive electron transfer from Sm(II) by stabilization of the radical anion intermediate rather than by solely promoting the first electron transfer as originally proposed. Notably, these studies suggest that all reactions involving the generation of ketyl-type radicals with SmI2 occur under a unified mechanism based on the thermodynamic control of the second electron transfer step, thus providing a blueprint for the development of a broad range of novel chemoselective transformations via open-shell electron pathways.