Transition metal-catalyzed pentannulation of propargyl acetates via styrylcarbene intermediates
作者:Yusuke Nakanishi、Koji Miki、Kouichi Ohe
DOI:10.1016/j.tet.2007.09.064
日期:2007.12
achieved by platinum or ruthenium catalysis via E-vinylcarbenoid intermediate. Considering the competitive reactions of pentannulation versus cyclopropanation, the equilibrium ratios of E and Z vinylcarbenoid intermediates from sec- and tert-propargyl esters are estimated at ca. 10:90 and 40:60, respectively. Two reaction pathways, Nazarov-type cyclization and/or metallacycle from styrylcarbenoid species
由苯基取代的仲和叔炔丙基酯(末端炔烃)形成的茚是通过铂或钌催化的E-乙烯基类胡萝卜素中间体而形成的。考虑到戊二醛与环丙烷化的竞争反应,估计仲和叔炔丙基酯的E和Z乙烯基类胡萝卜素中间体的平衡比约为1。分别是10:90和40:60。通过在对照实验中考虑产物的比例,提出了两种反应途径,即纳扎罗夫型环化和/或苯乙烯基类化合物产生的金属环。