Co(III)‐catalyzed [4+1] annulation of amides with allenes to synthesize isoindolone and 1,5‐dihydro‐pyrrol‐2‐one derivatives is reported. A wide range of aromatic and vinylic amides react with allenes to give the corresponding annulation products in good to excellent yields. The mechanistic studies strongly support that the catalytic reaction proceeds through an amide‐directed C−Hactivation, followed
new cobalt-catalyzed phenolic OH-assisted C–H functionalization of 2-vinylphenols with allenes to give various 2H-chromenes is described. It is the first time that allenes are used as the coupling partners in the cobalt-catalyzed C–H activation reactions. In most cases, cobalt-catalyzed oxidative annulation of arenes with alkenes or alkynes via C–H activation gave [4 + 2] or [3 + 2] cyclization products
Rh<sup>III</sup>-Catalyzed [4 + 1] Annulations of 2-Hydroxy- and 2-Aminobenzaldehydes with Allenes: A Simple Method toward 3-Coumaranones and 3-Indolinones
method for the regio- and stereoselective synthesis of substituted 3-coumaranones from salicylaldehydes and allenes using a rhodium(III) catalyst has been developed. This procedure gives access to new 2-vinyl-substituted 3-coumaranone compounds. The method involves a RhIII-catalyzed aldehyde C–H activation and annulationreactions. Moreover, this RhIII-catalyzed [4 + 1] annulationreaction has been applied
A cobalt-catalyzed C–H/N–H annulation of anilides with allenes to synthesize 1,2-dihydroquinolines is described. The reaction proceeds via a C–H activation, allene insertion, followed by β-hydride elimination and an intramolecular 1,4-addition to a butadiene-group-containing intermediate. Allenes act as a three-carbon source in the present C–H activation strategy.
A novel Rh(III)-catalyzed annulation of phthalazinones or pyridazinones with various allenes was developed, leading to the formation of indazole derivatives bearing a quaternary carbon in moderate to good yields. The targeted products were synthesized via sequential C–H activation and olefin insertion, followed by β-hydride elimination and intramolecular cyclization. The synthetic protocol proceeded
开发了一种新型 Rh( III ) 催化的酞嗪酮或哒嗪酮与各种丙二烯的环化反应,从而以中等至良好的产率形成带有季碳的吲唑衍生物。目标产物通过连续的C-H活化和烯烃插入,然后是β-氢化物消除和分子内环化来合成。合成方案有效地进行,具有广泛的官能团耐受性、高原子效率和高Z选择性。通过合成转化证明了该方法的实用性。