The straightforward synthesis of isochromene derivatives and related cyclic ethers is achieved by the rhodium-catalyzedoxidativecoupling of α,α-disubstituted benzyl and allyl alcohols with alkynes. The hydroxy groups effectively act as the key function for the regioselective C–H bond cleavage.
Ruthenium(II)-Catalyzed Synthesis of Isochromenes by CH Activation with Weakly Coordinating Aliphatic Hydroxyl Groups
作者:Sachiyo Nakanowatari、Lutz Ackermann
DOI:10.1002/chem.201400161
日期:2014.4.25
Cationic ruthenium(II) complexes have been employed for the highly effective oxidative annulation of alkynes with benzyl alcohols to deliver diversely decorated isochromenes. The hydroxyl‐directed CH/OH functionalization process proceeded efficiently under an atmosphere of air. Detailed mechanistic studies were indicative of a kinetically relevant CH metalation.
阳离子钌(II)配合物已被用于炔烃与苄醇的高效氧化环合反应,以提供装饰多样化的异色酮。羟基定向Ç H / O ħ官能化过程的空气的气氛下有效地进行。详细机理研究都表示动力学相关的C ^ h金属化。
Rhodium-catalyzed Carbonylative Annulation of 2-Bromobenzylic Alcohols with Internal Alkynes Using Furfural via β-Aryl Elimination
made in transformations of unstrained benzylic (tert-)alcoholsthrough β-aryl elimination, catalytic carbonylation has not yet been developed extensively because alkoxycarbonylation is probably favored over β-aryl elimination. In this letter, we report on the rhodium(I)-catalyzed carbonylative annulation of α,α-dimethyl-(2-bromoaryl)methanols with internal alkynes using furfural leading to the formation
Palladium mediated domino reaction: synthesis of isochromenes under aqueous medium
作者:Lavisha Punia、Karu Ramesh、Gedu Satyanarayana
DOI:10.1039/c9ra08792c
日期:——
Isochromenes have been synthesized using palladium-catalyzed C–C and C–O bond forming reactions starting from ortho-bromo tertiary benzylicalcohols and internal acetylenes. Notably, this domino process is feasible by using the green solvent, water. The protocol exhibited a broad substrate scope and afforded various isochromenes.
Palladium-catalyzed annulation of internal alkynes in aqueous medium
作者:Wei Jie Ang、Chih-Hsuan Tai、Lee-Chiang Lo、Yulin Lam
DOI:10.1039/c3ra46010j
日期:——
To facilitate precatalyst recovery and reuse, we have developed a fluorous, oxime-based palladacycle 1 and demonstrated that it is a very efficient and versatile precatalyst for carbo- and heteroannulation of internal alkynes with functionalized aryl halides in aqueous medium. A uniform reaction condition for these annulation reactions was also developed.