The stereoselectivesynthesis of the macrolactonecore of the natural product koshikalide is described. Starting with readily available 1,4-butanediol and malic acid as synthons, our synthetic strategy involved the reiterative application of Gilman’s reaction, Swern oxidation and Sharpless asymmetric epoxidation to establish the required stereocentres. Other key steps in the synthesis include Negishi
Photochemical Alkene Isomerization for the Synthesis of Polysubstituted Furans and Pyrroles under Neutral Conditions
作者:Johannes C. L. Walker、Simon Werrel、Timothy J. Donohoe
DOI:10.1002/chem.201903590
日期:2019.10.11
A photochemical approach to polysubstituted heterocycles using UV-induced alkene isomerization is described. The method allows for the synthesis of disubstituted furans and pyrroles under mild and neutral conditions and also provides access to a class of trisubstituted furans pertinent to natural-product synthesis. The method has broad functional-group tolerance and many richly decorated heterocycles
Stereochemistry of the 1,2-Wittig rearrangement: A synthesis of syn-1,3-diol monoethers
作者:Stuart L. Schreiber、Mark T. Goulet
DOI:10.1016/s0040-4039(00)95906-9
日期:——
The [1,2] Wittig rearrangement of β-alkoxyalkyl allyl ethers has been studied and found to provide syn-1,3-diol derivatives in 14–32% yield and with useful levels of diastereoselection.
Sparteine free Hoppe–Matteson–Aggarwal rearrangement was applied to various chiral acetonides. Utilizing different vinyl boronic esters a high level of substrate control was observed leading to excellent selectivities. These selectivities were attributed to stereoelectronic effects of the neighboring acetonide moiety. The obtained formal Felkin and anti-Felkin products feature up to four contiguous