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.
Department of Chemistry, Columbia University, 3000 Broadway, New York, New York 10027, USA.
Paul A
PA
Vadola
Dalibor
D
Sames
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