A novel domino reaction, alkyne-mediated domino hydroformylation/double cyclization, has been developed for rapid preparation of indolizidine type alkaloids. DFT calculations were applied for rationales of reactivity and selectivity. A concise synthesis of tashiromine as the application of the methodology is also reported.
Reactions of Transition-Metal η<sup>1</sup>-Propargyl and η<sup>1</sup>-Allenyl Complexes with Sulfur Dioxide and Transition-Metal−Carbon Bond-Cleaving Reactions of the Cycloadducts Which Yield Cyclic Sulfenate Esters
作者:Allison L. Hurley、Mark E. Welker、Cynthia S. Day
DOI:10.1021/om980006l
日期:1998.6.1
η1-allenyl complexes is reported. The 3 + 2 cycloaddition reactions of these complexes with sulfurdioxide yielded regioisomeric transition-metal-substituted 1,2-oxathiolen-1-yl oxides (sulfenate esters). One of the η1-allenyl complex SO2 cycloadducts has been characterized by X-ray crystallography. The transitionmetal can subsequently be cleaved from the sulfenate ester containing complexes under oxidative
involving 1,3-diene, alkyne, and silylene to afford silicon-containing seven-memberedrings was established. In the presence of a rhodium catalyst bearing bis(diphenylphosphino)methane (DPPM), nona-1,3-dien-8-yne derivatives reacted efficiently at 80–110 °C with boryl(isopropoxy)silane or boryl(diethyamino)silane, which reacts as the synthetic equivalent of silylene, to afford 1-silacyclohepta-2,5-dienes (2
建立了铑催化的[4 + 2 + 1]环加成反应,该反应涉及1,3-二烯,炔烃和亚甲硅烷基,以提供含硅的七元环。在带有双(二苯基膦基)甲烷(DPPM)的铑催化剂的存在下,壬基1,3-三烯-8-炔衍生物在80–110°C下与硼基(异丙氧基)硅烷或硼基(二乙氨基)硅烷有效反应,其作为亚甲硅烷基的合成当量反应,得到1-silacyclohepta-2,5-二烯(2,5-二氢-1 H-西勒平)。七元非共轭二烯的区域发散性和化学和立体选择性官能化是通过Cs 2 CO 3或铱催化剂介导的硼氢化作用实现的。