Iron(II)-Catalyzed Activation of Si-N and Si-O Bonds Using Hydroboranes

Mirela A Farcaş-Johnson; Danila Gasperini; Andrew K King; Sakshi Mohan; Adam N Barrett; Samantha Lau; Mary F Mahon; Yann Sarazin; Sara H Kyne; Ruth L Webster

doi:10.1021/acs.organomet.3c00339

Iron(II)-Catalyzed Activation of Si-N and Si-O Bonds Using Hydroboranes

Organometallics. 2023 Oct 4;42(20):3013-3024. doi: 10.1021/acs.organomet.3c00339. eCollection 2023 Oct 23.

Authors

Affiliations

¹ Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom.
² School of Chemistry, Faculty of Science, University of New South Wales, Sydney, NSW 2052, Australia.
³ Institut des Sciences Chimiques de Rennes, Université de Rennes, Campus de Beaulieu, 35042 Rennes, France.

Abstract

We report the activation and functionalization of Si-N bonds with pinacol borane catalyzed by a three-coordinate iron(II) β-diketiminate complex. The reactions proceed via the mild activation of silazanes to yield useful hydrosilanes and aminoboranes. The reaction is studied by kinetic analysis, along with a detailed investigation of decomposition pathways using catecholborane as an analogue of the pinacol borane used in catalysis. We have extended the methodology to develop a polycarbosilazane depolymerization strategy, which generates hydrosilane quantitatively along with complete conversion to the Bpin-protected diamine. The analogous Si-O bond cleavage can also be achieved with heating, using silyl ether starting materials to generate hydrosilane and alkoxyborane products. Depolymerization of poly(silyl ether)s using our strategy successfully converts the polymer to 90% Bpin-protected alcohols.