C-H bond functionalization via hydride transfer: direct coupling of unactivated alkynes and sp(3) C-H bonds catalyzed by platinum tetraiodide.
We report a catalytic intramolecular coupling between terminal unactivated alkynes and sp(3) C-H bonds via through-space hydride transfer (HT-cyclization of alkynes). This method enables one-step preparation of complex heterocyclic compounds by alpha-alkenylation of readily available cyclic ethers and amines. We show that PtI(4) is an effective Lewis acid catalyst for the activation of terminal alkynes for hydride attack and subsequent C-C bond formation. In addition, we have shown that the activity of neutral platinum salts (PtX(n)) can be modulated by the halide ligands. This modulation in turn allows for fine-tuning of the platinum center reactivity to match the reactivity and stability of selected substrates and products.
Vadola
Paul A
PA
Department of Chemistry, Columbia University, 3000 Broadway, New York, New York 10027, USA.
Sames
Dalibor
D
D000480:Alkynes / Q000737:chemistry*; D000588:Amines / Q000138:chemical synthesis / Q000737:chemistry; D002384:Catalysis; D004988:Ethers, Cyclic / Q000138:chemical synthesis / Q000737:chemistry; D006571:Heterocyclic Compounds / Q000138:chemical synthesis / Q000737:chemistry; D015394:Molecular Structure; D017671:Platinum Compounds / Q000737:chemistry*
D000480:Alkynes; D000588:Amines; D004988:Ethers, Cyclic; D006571:Heterocyclic Compounds; D017671:Platinum Compounds; C547017:platinum tetraiodide