Gold(I) catalysed cycloisomerisation of β-hydroxy propargylic esters to dihydropyrans/2H-pyrans via allene intermediates
作者:Ramesh Kotikalapudi、K.C. Kumara Swamy
DOI:10.1016/j.tet.2013.07.003
日期:2013.9
Efficient cycloisomerisation of β-hydroxy propargylic esters to dihydropyrans/2H-pyrans via 1,3-carboxylate migration followed by regioselective hydroxyl addition to the transient allene intermediate catalysed by Ph3PAuCl/AgSbF6 is presented. Similar reactions on phosphorylated precursors led to phosphono-furans and phosphono-pyrans. In a few cases, self-condensation of β-hydroxy propargylic esters
Azepine Synthesis from Alkyl Azide and Propargylic Ester via Gold Catalysis
作者:Heng Liu、Xin Li、Zili Chen、Wen-Xiang Hu
DOI:10.1021/jo300667a
日期:2012.6.1
multisubstituted 4, 5-dihydro-1H-azepine derivatives through the gold-catalyzed reaction of two molecules of propargylic esters with one molecule of alkyl azide. It was proposed that vinyl gold carbenoid, in situ generated from propargylic ester through gold-catalyzed 1, 2-rearrangement, was trapped by alkyl azide to give vinyl imine intermediate. These, in turn, could undergo a formal [4 + 3] cycloaddition with
通过金催化两分子炔丙酸酯与一分子烷基叠氮化物的金催化反应,开发了一种有效的新方法来合成多取代的4、5-二氢-1 H - ze庚因衍生物。有人提出,用烷基叠氮化物捕获炔丙基酯通过金催化的1、2-重排原位生成的乙烯基金类胡萝卜素,得到乙烯基亚胺中间体。这些反过来可能会与另一分子乙烯基金类胡萝卜素进行正式的[4 + 3]环加成反应,从而提供所需的氮杂产物。
NHC–gold(<scp>i</scp>) catalysed [4 + 2] cycloaddition–acyclic addition of dialkyl substituted propargylic esters with 1,3-diphenylisobenzofuran: synthesis of novel benzo[c]fluorenols and substituted dienes
作者:Ramesh Kotikalapudi、A. Leela Siva Kumari、K. C. Kumara Swamy
DOI:10.1039/c4ra01105h
日期:——
A gold carbene complex [IPrAuCl/AgSbF6] catalysed novel cycloaddition of propargylic esters with 1,3-diphenylisobenzofuran is reported. A [4 + 2] cycloaddition followed by sequential aromatic allylation leading to pentannulation with the expulsion of benzoic acid, then 1,2-phenyl migration coupled with ring opening and aromatisation leading to a new class of benzofluorenols, is discovered. This process