Yu Robert T, Rovis Tomislav
Department of Chemistry, Colorado State University, Fort Collins, CO 80523, USA.
J Am Chem Soc. 2006 Mar 8;128(9):2782-3. doi: 10.1021/ja057803c.
A rhodium(I)-catalyzed [2 + 2 + 2] cycloaddition between alkenyl isocyanates and alkynes has been developed. Heating a mixture of an alkenyl isocyanate and a symmetrical internal alkyne in the presence of [Rh(ethylene)2Cl]2/P(4-OMe-C6H4)3 in toluene delivers substituted indolizinones and quinolizinones. Depending on the substrates, a rare fragmentation of the isocyanate unit can be involved within the cycloaddition process to furnish a vinylogous amide embedded in the indolizinone.
已开发出一种铑（I）催化的烯基异氰酸酯与炔烃之间的[2 + 2 + 2]环加成反应。在甲苯中，[Rh(乙烯)₂Cl]₂/P(4-甲氧基-C₆H₄)₃存在下，加热烯基异氰酸酯和对称内炔的混合物，可得到取代的中氮茚酮和喹嗪酮。根据底物的不同，在环加成过程中可能会发生异氰酸酯单元罕见的断裂，从而形成嵌入中氮茚酮中的烯醇酰胺。
