Diverse Synthesis of Alkenylsilanes via Pd-Catalyzed Alkenyl C-H Silylation.

Here, we disclose a general approach for the diverse synthesis of alkenylsilanes in a highly efficient, stereoselective, and atom-economic manner by leveraging the palladium-catalyzed disilylation reaction of 2-bromostyrene derivatives with hexamethyldisilane, which is suitable for the preparation of a series of disubstituted, trisubstituted, and tetrasubstituted alkenylsilanes. Furthermore, the resulting tetrasubstituted alkenylsilanes could be readily transformed into the corresponding diarylated benzosiloles, which have been proven to be a potential AIE material and a fluorene material.

Synthesis of Azepane Derivatives via Formal 1,3-Migration of Hydroxy and Acyloxy Groups and Selective Annulation.

Formal 1,3-migration of hydroxy and acyloxy groups initiated by α-imino rhodium carbene was achieved, and the following selective annulations of the corresponding zwitterions could efficiently afford azepane derivatives. Benefiting from a time-saving procedure as well as a good functional group tolerance, this unique migration-annulation protocol could provide an efficient tool for synthesizing seven-membered N-heterocycles. The plausible mechanism is discussed.

Microbiota derived butyrate affected the muscle texture of Nile tilapia (Oreochromis niloticus) fed with different protein sources.

Flesh quality is influenced by diet components, but the underlying mechanism remains unclear. This study aimed to investigate the effect of replacing soybean meal (SBM) protein with cottonseed protein concentrate (CPC) at different levels (0%, CK; 15%, CPC15; 30%, CPC30 and 45%, CPC45) on the flesh quality of Nile tilapia. The results indicated that different protein sources influenced muscle amino acid composition instead of fatty acid composition. Lower muscle lipid content was found in CPC45, which in turn significantly altered the muscle texture. The hepatic lipid metabolism-related genes were detected and we found that CPC45 significantly suppressed the lipogenesis and promoted lipolysis. Higher content of microbiota-derived butyrate was found in the intestinal content of CPC45 and butyrate could decrease the lipid accumulation in vitro. Replacing SBM with CPC increased the intestinal butyrate to suppress the lipogenesis in the liver which may account for the increased muscle hardness.

Enantioselective Synthesis of Silicon-Stereogenic Monohydrosilanes by Rhodium-Catalyzed Intramolecular Hydrosilylation.

Enantiopure monohydrosilanes are versatile chiral reagents for alcohol resolution and mechanistic investigation. Herein, we have demonstrated the asymmetric synthesis of monohydrosilanes via an intramolecular hydrosilylation strategy. This protocol is suitable for the synthesis of five- and six-membered cyclic monohydrosilanes, including a class of chiral oxasilacycles, with excellent diastereo-, regio-, and enantioselectivities. Notably, the catalyst loading could be reduced to 0.1 mol % which makes this one of the most efficient methods to access chiral monohydrosilanes. Mechanistic studies and DFT calculations indicate this Rh-catalyzed intramolecular asymmetric hydrosilylation reaction might proceed via a Chalk-Harrod mechanism, and the enantio-determining step was predicted to be oxidative addition of Si-H bond.

Synthesis of benzothiazonine by rhodium-catalyzed denitrogenative transannulation of 1-sulfonyl-1,2,3-triazole and thiochromone.

A facile synthesis of multi-functionalized benzothiazonine was achieved by the rhodium-catalyzed denitrogenative annulation of 1-sulfonyl-1,2,3-triazole and thiochromone. In view of the excellent atom economy, broad substrate scope and easy availability of starting materials, the protocol provided an efficient strategy for the construction of medium N,S-heterocycles.

Efficient dehydrative alkylation of thiols with alcohols catalyzed by alkyl halides.

Alcohols can be efficiently converted into the useful thioethers by a transition metal- and base-free dehydrative S-alkylation reaction with thiols or disulfides by employing alkyl halides as the effective catalyst. This simple and efficient method is a green and practical way for the preparation of thioethers, as it tolerates a wide range of substrates such as aryl and alkyl thiols, as well as benzylic, allylic, secondary, tertiary, and even the less reactive aliphatic alcohols.