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A KO t Bu-catalyzed ring-opening gem -silylborylation of cyclopropenes with silylboronates has been developed for the synthesis of (1-silyl)allylboronates, a useful class of compounds in organic synthesis. The reaction proceeds with high selectivity under mild conditions, and the reaction mechanism has been theoretically investigated using DFT calculations.

A palladium-catalyzed synthesis of benzosilacyclobutenes has been developed via position-selective C(sp 3 )-H bond activation, including those having substituents at the methylene carbon on the 4-membered silacycle. The obtained products could be engaged in the palladium- or nickel-catalyzed ring-expansion reactions to give compounds possessing 6-membered silacycles.

A palladium-catalyzed synthesis of 4-sila-4 H -benzo[ d ][1,3]oxazines, silicon-switched analogs of biologically relevant 4 H -benzo[ d ][1,3]oxazines, was developed by the intramolecular Hiyama coupling of 3-amido-2-(arylsilyl)aryl triflates. The present reaction is an unusual way of utilizing the Hiyama coupling, enabling the synthesis of value-added organosilanes as the main products. The intramolecular nature of transmetalation with inversion of the stereochemistry at the silicon center was revealed by the mechanistic investigation, and an asymmetric variant of this process was also demonstrated to give silicon-stereogenic 4-sila-4 H -benzo[ d ][1,3]oxazines with relatively high enantioselectivity., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Anionic stitching polymerization of styryl(vinyl)silanes has been developed for the synthesis of a new type of silicon- and carbon-containing polymer possessing fused sila-bicyclic structures in the main chain. The obtained polymers were found to be thermally stable with relatively high glass-transition temperatures and highly transparent in the visible light region.

A new cyclopropanation reaction of allyl phosphates with lithium phosphides has been developed to give cyclopropylphosphines through the formation of both a C-P bond and a cyclopropane ring at the same time, and high selectivity toward cyclopropanation over allylic substitution has been realized by conducting the reaction in the presence of HMPA.

Various carbonyl-bridged dibenzofulvalenes were synthesized by a sequence of rhodium-catalyzed stitching reaction and post-functionalization, and their optical and electronic properties could be tuned by changing the terminal substituents. The present stitching reaction also allowed for facile synthesis of dibenzofulvalenes having C, Si, Ge, S, and P as the bridging elements.

A rhodium-catalysed stitching reaction between 2-(silylethynyl)arylboronates and 2-(silylethynyl)aryl bromides has been developed for the synthesis of unsymmetric dibenzo[ a , e ]pentalenes. The introduction of appropriately sized silyl groups on the starting substrates led to a high crossover selectivity without using an excess amount of either substrate. The present stitching reaction could produce a variety of unsymmetric dibenzo[ a , e ]pentalene derivatives, including those with electronically different substituents on the fused benzene rings as well as heteroarene fused compounds. Desilylative halogenation was also demonstrated to synthesise the corresponding halogenated dibenzo[ a , e ]pentalenes, which can be used as building blocks for further chemical transformations.

A rhodium-catalyzed regio- and enantioselective synthesis of silicon-stereogenic silicon-bridged arylpyridinones has been developed through [2 + 2 + 2] cycloaddition of silicon-containing prochiral triynes with isocyanates. High yields and enantioselectivities have been achieved by employing an axially chiral monophosphine ligand, and this process could be applied to catalytic asymmetric synthesis of silicon-stereogenic chiral polymers for the first time. The reaction mechanism of the present catalysis has also been experimentally investigated to establish a reasonable catalytic cycle, advancing the mechanistic understanding of the rhodium-catalyzed pyridinone synthesis by [2 + 2 + 2] cycloaddition reactions.

Rhodium-catalyzed intramolecular alkynylsilylation of alkynes is described. The reaction proceeds through syn-insertion by a cationic rhodium/triarylphosphine catalyst, representing the first alkynylsilylation of alkynes via the cleavage of a C(sp)-Si bond by transition-metal catalysis. A highly enantioselective variant is also described for the creation of a silicon stereogenic center.

A simple and efficient catalyst removal system has been developed in the cobalt-salen-catalyzed copolymerization of propylene oxide with carbon dioxide. The present system requires no prior modification of the catalyst, and the removal is achieved by simple addition of myristic acid, followed by organic liquid-liquid phase separation.

A palladium-catalyzed asymmetric synthesis of 2-pyrrolidinones with a quaternary stereocenter at the 3-position has been achieved by the reaction of γ-methylidene-δ-valerolactones with alkyl isocyanates. High enantioselectivity has been realized by employing a newly synthesized chiral phosphoramidite ligand.

Novel chiral phosphorus-olefin bidentate ligands have been synthesized in a few steps from a readily available enantiopure compound. These ligands have been applied to a rhodium-catalyzed asymmetric addition of organoboroxines to N-sulfonyl aldimines, achieving high yield and enantioselectivity.

A palladium-catalyzed decarboxylative cyclopropanation of 2-alkylidenetrimethylene carbonates with isocyanates is described to form oxazolidinones of (1-aminocyclopropyl)methanols with high selectivity. The site of nucleophilic attack is directed by connecting the two reaction components and by employing an electron-deficient triarylphosphine ligand.

A copper-catalyzed addition of arylboronates to isatins has been developed to give 3-aryl-3-hydroxy-2-oxindoles under mild conditions. The catalytic cycle of this process has been examined through a series of stoichiometric reactions and an effective asymmetric variant has also been described by the use of a chiral N-heterocyclic carbene ligand.

A palladium-catalyzed intramolecular decarboxylative cyclization of alpha-aryl-gamma-methylidene-delta-valerolactones, followed by olefin isomerization, has been developed to give fused polycyclic aromatic compounds under mild conditions. The process described here can be regarded as a formal decarboxylative allylic arylation without using a pre-formed organometallic nucleophile. The reaction can be conducted on a gram scale and the products thus obtained are further derivatized with ease.

A rhodium/binap complex has been found to effectively catalyze the isomerization of unactivated internal alkynes to the corresponding 1,3-dienes in the presence of an azomethine imine as the reaction promoter.

Rhodium/chiral diene (S,S)- complex has been found to effectively catalyze the 1,4-addition of arylboronic acids to alpha,beta-unsaturated Weinreb amides, furnishing useful beta-chiral Weinreb amides in high enantioselectivity.