An efficient preparative method for the synthesis of siloxanols based on aerobic Co(OAc)2 or Cu(OAc)2/NHPI-catalyzed oxidation of hydride siloxanes has been proposed.

Synthesis of organosilicon products with a "polar" functional group within organic substituents is one of the most fundamentally and practically important challenges in today's chemistry of silicones. In our study, we suggest a solution to this problem, viz., a high-efficiency preparative method based on aerobic Co-/N-hydroxysuccinimide (NHSI) catalyzed oxidation of p-tolylsiloxanes to p-carboxyphenylsiloxanes. This approach is based on "green", commercially available, simple, and inexpensive reagents and employs mild reaction conditions: Co(OAc) 2 /NHSI catalytic system, O 2 as the oxidant, process temperature from 40 to 60 °C, atmospheric pressure. This reaction is general and allows for synthesizing both mono-and di-, tri-, and poly(p-carboxyphenyl)siloxanes with p-carboxyphenyl groups at 1,1-, 1,3-, 1,5-, and 1,1,1-positions. All the products were obtained and isolated in gram amounts (up to 5 g) and in high yields (80−96%) and characterized by NMR, ESI-HRMS, GPC, IR, and X-ray data: p-carboxyphenylsiloxanes in crystalline state form HOF-like structures. Furthermore, it was shown that the suggested method is applicable for the oxidation of organic alkylarene derivatives (Ar−CH 3 , Ar−CH 2 −R) to the corresponding acids and ketones (Ar−C(O)OH and Ar−C(O)−R), as well as hydride silanes ([Si]−H) to silanols ([Si]−OH). The possibility of synthesizing monomeric (methyl) and polymeric (siloxane-containing PET analogue, Sila-PET) esters based on 1,3-bis(p-carboxyphenyl)disiloxane was studied. These processes occur with retention of the organosiloxane frame and allow to obtain the corresponding products in 90 and 99% yields.

Frustrated Lewis pairs consisting of diphenylphosphino and boryl groups located at the ortho‐position can trap difluorocarbene affording stable zwitterionic adducts. The reaction can be reversed to release difluorocarbene at elevated temperatures.

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A readily accessible reagent bearing ortho-oriented amino and boryl groups efficiently traps difluorocarbene.

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The first selective process of formal [2+2]‐cycloaddition of donor–acceptor cyclopropanes (DAC) to multiple C–C bonds to form a four‐membered ring in the product has been developed. Bicyclobutylidene is used do demonstrate this reaction. The process is promoted by GaCl3 and occurs through generation of 1,2‐zwitterionic intermediates. A carbocationic rearrangement occurs in the bicyclobutylidene moiety. It results in expansion of both cyclobutane rings into five‐membered ones and formation of a [2.3.3]propellane skeleton in the final product.

1,2-Bis(pyrid-4-yl)ethylene (red) and 2-allylmalonate (blue) undergo a photoinitiated [2+2] crossed cycloaddition reaction in a 3D coordination polymer, accompanied with significant atomic movement and crystal decomposition.