Efficient Hydroboration of Esters and Nitriles Using a Quinazolinone-Supported Titanium(IV) Multitasking Catalyst |
| |
Authors: | Rajrani Narvariya Dr Suman Das Susmita Mandal Dr Archana Jain Prof Tarun K Panda |
| |
Institution: | 1. Department of Chemistry, Indian Institute of Technology Hyderabad Kandi –, 502284 Sangareddy, Telangana, India;2. Department of Physics & Chemistry, Mahatma Gandhi Institute of Technology (MGIT) Gandipet-, 500075 Hyderabad, India |
| |
Abstract: | We report catalytic hydroboration of esters as well as nitriles under solvent-free and mild conditions using single titanium(IV) metal complex, {κ2-C6H4C(O)N(iPr)C(N-iPr)=N}{κ3-(iPr)N=C(O)−C6H4−NC(NMe2)N(iPr)}TiNMe2] 1 as a sustainable, economical, and efficient pre-catalyst. The molecular structure of the TiIV complex in the solid state reveals the unique coordination of TiIV metal with N, N, and O atoms of one quinazolinone unit via in-situ rearrangement, while another quinazolinone moiety coordinates in bidentate fashion via both N atoms only. The TiIV complex demonstrates excellent activity as a pre-catalyst towards the hydroboration of a wide array of esters and nitriles with pinacolborane (HBpin) to afford alkoxyboranes and diboryl amines in high yield (up to 99 %) with greater tolerance to a variety of electron-withdrawing and electron-donating functional groups. A most plausible mechanism of hydroboration of esters is also proposed based on kinetics and NMR studies, which suggests the formation of titanium-hydride species as an active catalyst. |
| |
Keywords: | Aryl/alkylboryl ether Diboryl amine Hydroboration Titanium Quinazolinone |
|
|