Hydrosilanes are convenient reductants for a large variety of organic oxygenated substrates and they have been successfully applied in the conversion of bio-based materials1 and CO2.2 Hydrosilanes are however produced via energy intensive processes3 and they generate, after use, silicon oxides wastes such as siloxanes, which are difficult to recycle. These limitations call for the development of catalytic processes able to transform Si‒O bonds in siloxanes into Si‒H hydrides. Previous reports4 have shown that chlorosilanes can be prepared from siloxanes by treatment with HCl. Catalytic methods that would convert Si‒Cl linkages into Si‒H hydrides are thus particularly attractive. We report here an efficient hydrogenolysis of chlorosilanes using [(tBuPOCOP)IrHCl] complex in mild conditions with selective formation of hydrosilanes in high yields (up to 79 %). These results represent an important step forward compared to the only example of hydrogenolysis of Si‒Cl bonds (7 %) reported by Shimada5. This very good performance was driven by the use of guanidine bases and have been rationalized based on NMR investigations and DFT calculations.

References 
1.	L. Monsigny, E. Feghali, J.-C. Berthet and T. Cantat, Green Chem., 2018, 20, 1981.
2.	S.N. Riduan, , Y. Zhang and J.Y. Ying, Angew. Chem. Int. Ed., 2009, 48, 3322.
3.	W. Kalchauer, B. Pachaly, In Handbook of Heterogeneous Catalysis.Wiley, 2008, 2635-2647.
4.	P. A. Di Giorgio, W. A. Strong, L. H. Sommer and F. C. Whitmore J. Am. Chem. Soc., 1946, 68, 7, 1380 ; D. L. Bailey, L. H. Sommer and F. C. Whitmore J. Am. Chem. Soc., 1948, 70, 1, 435-436 ; S. Masaoka, T. Bannoa, M. Ishikawa  J. Organomet. Chem., 2006, 691, 1–2, 174-181 ; J. M. Roberts, D. V. Eldred, D. E. Katsoulis Ind. Eng. Chem. Res., 2016, 55, 6, 1813-1818. 
5.	(a) D. Tsushima, M. Igarashi, K. Sato and S. Shimada, Chem. Lett., 2017, 46, 1532–1534. 
See also hydrogenolysis of chlorosilanes in the presence of additives (NaI, NaBPh4F) : (b) T. Beppu, K. Sakamoto, Y. Nakajima, K. Matsumoto, K. Sato and S. Shimada, J. Org. Chem., 2018, 869, 75-80. (c) A. Glüer, J. I. Schweizer, U. S. Karaca, C. Würtele, M. Diefenbach, M. C. Holthausen and S. Schneider, Inorg. Chem., 2018, 57 (21), 13822-13828.

Catalytic Hydrogenolysis of Silyl Triflates and Chlorides Using Iridium Pincer Complexes and (Super)bases

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