OSW‐1 is a well‐known natural saponin with potent antitumor activities. We have designed and prepared a small library of 22 OSW‐1analogues with a variety of p‐acylamino‐benzoyl groups installed at C2” of the xylose residue, wherein a regioselective (1→3)‐glycosylation of arabinoside 3,4‐diol has been achieved by manipulation of the protecting groups on the imidate donors. Bioassays lead to new structure‐activity
Studies on the synthesis of linear aliphatic compounds. Part 2. The realisation of a strategy for repeated molecular doubling.
作者:Eva Igner、Oliver I. Paynter、Derek J. Simmonds、Mark C. Whiting
DOI:10.1039/p19870002447
日期:——
starting-materials, obtainable free from near homologues, to compounds of doubled chain length have been explored as approaches to the synthesis of n-paraffins and of terminally mono- or bi-functional derivatives. Acetylene alkylation routes lead to problems with protecting groups, but the use of the Wittig reaction provides a method of moleculardoubling convenient for repeated use, with the formation of chain-lengths
Construction of [2,5]-Furanophanes by Carbene-Mediated Alkynyl Migration Cyclization
作者:Qiu Shi、Yang Chen、Tongxiang Cao、Shifa Zhu
DOI:10.1021/acs.orglett.2c03185
日期:2022.11.11
Heterophanes are widely found in natural products and drug molecules. Herein, an efficient method for the construction of [2,5]-furanophanes with differentring types and ringsizes was developed. This method is carried out with furan-free precursor throughintramolecular carbene-mediated alkynyl migration and tandem cyclization strategy. In addition, a series of tetrafuran structures can be obtained by oxidative
V-MPS4 catalyst was reusable up to six times without a significant loss in the product yield. The advantages of using the heterogeneous catalyst were further demonstrated by conducting the deprotection reaction in a continuous flow process, which resulted in a 2.7-fold higher catalyst turnover number and 60-fold higher turnover frequency compared to those of the corresponding batch reaction. Fullsize
<i>Anti-</i>Carbometalation of Homopropargyl Alcohols and Their Higher Homologues via Non-Chelation-Controlled <i>Syn</i>-Carbometalation and Chelation-Controlled Isomerization