shintaro takahashi

Se-Aryl-N-phenylphenoselenazinium salts were synthesized as triarylselenonium salts incorporating a photosensitizer unit. Under blue-light irradiation, these served as aryl radical precursors, yielding arylphosphonates, phenol, and phenylboronic ester. The reaction mechanism was...

We designed and synthesized a series of three‐coordinated stannylenes featuring an amino‐linked NHC ligand, specifically tailored for the hydroboration of carbonyl compounds and imines. To fine‐tune the catalytic performance both sterically and electronically, various substituents (chloro, triflate, and bis(trimethylsilyl)amino groups) were introduced at the tin center, generating structurally diverse stannylenes. The hydroboration of carbonyl compounds catalyzed by these stannylenes proceeded under mild reaction conditions, affording the corresponding boryl esters in excellent yields with high chemoselectivity. Notably, bis(trimethylsilyl)aminostannylene exhibited outstanding catalytic efficiency, enabling hydroboration with a minimal catalyst loading of 0.01 mol% for aldehydes and 0.1 mol% for ketones, and was tolerant of a wide range of substrates, including sterically hindered and electronically diverse carbonyl compounds. Furthermore, in the hydroboration of imines, the reaction proceeded efficiently with just 5 mol% catalyst, furnishing the corresponding borylamines in high yields. Based on stoichiometric experiments, we propose a plausible catalytic cycle for stannylene‐mediated hydroboration.

An isolable monomeric alumylene stabilized by two donating ligands (phosphine and NHC) has been synthesized. Experimental and theoretical analysis confirms that the NHC ligand in the Al(I)‐complex is labile and reversibly dissociates from the AlI center above ‐20 °C. Of particular interest, despite being thermodynamically stabilized by the two ligands, alumylene complex exhibits a high reactivity with a considerably higher nucleophilicity compared to the mono‐ligated complex. It is interesting to note that the Al(I)‐complex reacts immediately with N2O at ‐90 °C, allowing the synthesis of bisligated aluminum oxide, which is stable up to ‐70 °C.

<jats:p>Iminophosphonamido-supported silylaminostannylenes activate CO₂ to afford siloxystannylene and isocyanates via carbamatostannylene intermediates. DFT calculations support a two-step rearrangement involving nucleophilic attack and silyl migration, offering a rare example of a...</jats:p>

We report an original reactivity of base‐stabilized C‐phosphonio‐silyne with N2O allowing the synthesis of a base‐stabilized diazosilenyl cation. This silicon analogue of diazoalkenes exhibits a remarkable stability thanks to ligand coordination. In addition, a particular stabilizing effect of the silicon atom of diazoalkene moiety was predicted by DFT calculations.