A Stereoselective Palladium-Mediated Reductive Coupling of Electron-Deficient Terminal Iodoalkenes
作者:Andrei S. Batsanov、Jonathan P. Knowles、Benedict Samsam、Andrew Whiting
DOI:10.1002/adsc.200700464
日期:2008.1.25
Iodoacrylate esters undergo palladium-catalysed reductive homocoupling to derive dienyl diester derivatives. This reductivecoupling can be extended to ester-substituted terminal iododienes to derive tetraene diesters. In all cases, the reactions show relatively high levels of stereocontrol, which shows an inversion of stereochemistry about one iodoalkene unit. This process, and the suggestion that the
A low temperature, vinylboronate ester-mediated, iterative cross-coupling approach to xanthomonadin polyenyl pigment analogues
作者:Katrina S. Madden、Jonathan P. Knowles、Andrew Whiting
DOI:10.1016/j.tet.2019.130657
日期:2019.11
Approaches to the polyene natural product xanthomonadin, an octaenyl electron-deficient bacterial photoprotective agent, and its debromo analogue, were developed. These involved the iterative cross-coupling of multiple C2-fragments, using a vinylboronate ester as a formal vinyl dianion equivalent. Vinyl iodide starting materials undergo Heck-Mizoroki cross-coupling at ambient temperatures, allowing further iododeboronation to derive the next vinyl iodide. This works in a highly effective manner to access systems of up to pentaene chain length. However, final assembly of polyenylboronates with such polyenyl iodides through their Suzuki-Miyaura cross-coupling was less successful, even at lower temperatures, reflecting the extreme sensitivity of such octaenylxanthomonadin analogues. Despite this, the mild cross-coupling conditions could be effectively applied to the assembly of a range of useful polyenyl building blocks, as well as a truncated pentaenyl-debromoxanthomonadin analogue. (C) 2019 Elsevier Ltd. All rights reserved.