Rhodium(I)‐Catalyzed Reductive Cyclocarbonylation of Internal Alkynes: Atom‐Economic Process for Synthesis of 2‐Cyclopenten‐1‐ones, 5‐Alkylidenefuran‐2(5 H)‐ones and Indan‐1‐ones

Abstract

The reductive cyclocarbonylation of internal alkynes with carbon monoxide catalyzed by [{RhCl(CO)(2)}(2)]/CO(NH(2))(2) in the presence of water has been investigated. Dialkyl alkynes underwent a reductive [2+2+1] cyclocarbonylation to afford selectively cis-2-cyclopenten-1-ones in high yields. In the cases of diarylacetylenes used, both trans-2-cyclopenten-1-ones and 5-alkylidenefuran-2(5 H)-ones were obtained, and the presence of electron-withdrawing group on the benzene ring enhanced the formation of 5-alkylidenefuran-2(5 H)-ones. On the other hand, ortho-substituted diarylacetylenes underwent a reductive [4+1] cyclocarbonylation to produce selectively indan-1-ones in good yields.

Recent Advances in the Synthesis of Indanes and Indenes

“…[66] The Rh I -catalyzed reductive cyclocarbonylation of diarylacetylenes 138 allowed the direct synthesis of 1-indanones 139. [67] The proposed mechanism involves the ortho CÀHa ctivation by oxidative addition to Rh I followed by triple bond insertion, carbon monoxide insertion and hydrogenolysis (from the mo-lecular hydrogen generated in situ from CO and water, Scheme56). [67] Another Rh I -catalyzed method for the synthesis of indanone derivatives 141 consisted in the hydroacylation of 2-vinylbenzaldehydes 140.…”

“…[67] The proposed mechanism involves the ortho CÀHa ctivation by oxidative addition to Rh I followed by triple bond insertion, carbon monoxide insertion and hydrogenolysis (from the mo-lecular hydrogen generated in situ from CO and water, Scheme56). [67] Another Rh I -catalyzed method for the synthesis of indanone derivatives 141 consisted in the hydroacylation of 2-vinylbenzaldehydes 140. [68] The process, catalyzedb yt he cationic species [Rh(dppe)] + under mild conditions (DCM,2 38C), occurred through oxidative addition of the formyl group to Rh I followed by double bond insertion and reductivee limination (Scheme 57).…”

“…Synthesis of 1-indanones 139 by Rh I -catalyzedcyclocarbonylation of diarylacetylenes 138. [67] Scheme57. Synthesis of 1-indanones 141 by Rh I -catalyzedhydroacylationo f 2-vinylbenzaldehydes 140.…”

C–H Activation and Alkyne Annulation via Automatic or Intrinsic Directing Groups: Towards High Step Economy

“…However, it is much more challenging for a linear alkyne group to direct on its ortho ‐site. In 2009, our group discovered an interesting substrate‐controlling divergent synthesis when investigating reactions using internal alkynes and carbon monoxide . For ortho ‐substituted aryl alkynes, C–H carbonylation was occurred to form [4+1] products instead of [2+2+1] cyclization using those unsubstituted substrates (Scheme ).…”

Base-Promoted Chemodivergent Formation of 1,4-Benzoxazepin-5(4H)-ones and 1,3-Benzoxazin-4(4H)-ones Switched by Solvents

“…As part of our continued interest in the development of the application of base/DMSO-promoted S N Ar reaction for the formation of C–N bond under transition-metal-free conditions [36,37,38], and the chemodivergent transformations of alkynes [39,40,41], as well as the new synthetic methods of heterocyclic compounds [42,43,44], we herein describe an efficient protocol for the formation of 1,4-benzoxazepin-5(4 H )-ones and 2-vinyl-1,3-benzoxazin-4(4 H )-ones via KOH-promoted solvent-controlled intermolecular cyclization reaction between substituted ortho -fluorobenzamide and 2-propyn-1-ol [45].…”