Carbene insertion reactions for the construction of C-C and C-heteroatom bonds using surface modified Silica microspheres as catalysts

Silica microspheres (SMs) feature non-toxic and high chemical stability, which have a wide range of applications in sensors, photosensitive emulsion and medicine. However, applying SMs as catalysts for synthesis of fine chemicals in organic and medical chemistry field has few been reported before. In this work, SMs were efficiently synthesized through hydrolysis and polycondensation reaction of ethyl orthosilicate (TEOS) in an alkaline system, and the surface modified SMs catalysts were successfully pre-pared by the impregnation method. The surface modified SMs catalyzed X -H (X = C, O, N, S) and C -C bonds insertion reactions from various diazo compounds with acyclic and cyclic 1,3-dicarbonyl com-pounds, arylamines and thiophenols were reported, giving the corresponding products in moderate to excellent yields. The modified species played the key role in the reactions and were identified as the cat-alytic active species. HRTEM and XRD revealed that the modified species are highly dispersed on the modified SMs surface.(c) 2023 Elsevier Inc. All rights reserved.