Three-Membered Aluminacycles.

Three-membered-ring scaffolds of carbocycles, namely, cyclopropanes and cyclopropenes, are ubiquitous in natural products and pharmaceutical molecules. These molecules exhibit a peculiar reactivity, and their applications as synthetic intermediates and versatile building blocks in organic synthesis have been extensively studied over the past century. The incorporation of heteroatoms into three-membered cyclic structures has attracted significant attention, reflecting fundamental differences in their electronic/geometric structures and reactivities compared to their carbon congeners and their associated potential for exploitation in applications.

A Three-Membered Diazo-Aluminum Heterocycle to Access an Al=C π Bonding Species.

[1+2] cycloaddition between a cyclic (alkyl)(amino)aluminyl anion (3) and diaryldiazomethane affords an AlN three-membered ring species (4). Compound (4) is thermally unstable and spontaneously releases N gas under the mild reaction condition to generate an ion-separated species 5. An X-ray study shows that the anionic part of 5 bears a considerable short exocyclic Al-C bond, and computational studies involving molecular orbital and natural bond orbital analysis indicate the Al=C π bonding character.

Diverse reactions of a fluorostannylenoid towards ethynes.

Fluoro(dialkyl)stannylenoid 2 exhibits unique reactivity towards ethynes with acetylenic hydrogen and those with trimethylsilyl groups, though the corresponding free dialkylstannylene 1 is inactive against those ethynes. Stannylenoid 2 reacts smoothly with gaseous ethyne and phenylethyne at room temperature, giving the corresponding diethynylstannanes, di(phenylethynyl)stannane 3 and diethynylstannane 6, respectively, in good yields with the concomitant evolution of H. Trimethylsilyl-substituted ethynes such as 1-trimethylsilyl-(2-phenyl)ethyne and 1,2-bis(trimethylsilyl)ethyne react similarly to give 3 and bis(trimethylsilylethynyl)stannane 8, respectively.

Synthesis and properties of hypervalent electron-rich pentacoordinate nitrogen compounds.

Isolation and structural characterization of hypervalent electron-rich pentacoordinate nitrogen species have not been achieved despite continuous attempts for over a century. Herein we report the first synthesis and isolation of air stable hypervalent electron-rich pentacoordinate nitrogen cationic radical () species from oxidation of their corresponding neutral () species. In the cationic radical species, the nitrogen centers adopt a trigonal bipyramidal geometry featuring a 3-center-5-electron hypervalent attractive interaction.

Dihydrogen Splitting Using Dialkylsilylene-Based Frustrated Lewis Pairs.

Isolable dialkylsilylene 5 reacts with dihydrogen in the presence of a small amount of a conventional Lewis acid (BPh , BEt ) or a base (PPh , PEt , NPh , NEt ) at low temperatures in a hydrocarbon solvent, giving the corresponding dihydrosilane 10 in high yields. Both 5/Lewis acid and Lewis base/5 pairs work as a frustrated Lewis pair (FLP) to split dihydrogen, being in accord with the amphoteric nature of silylene 5.

Reversible Stannylenoid Formation from the Corresponding Stannylene and Cesium Fluoride.

A fluorostannylenoid (Cs [R SnF] (9), R =(TMS) CCH CH C(TMS) ) was prepared by reacting a stable dialkylstannylene (R Sn (8), R =(TMS) CCH CH C(TMS) ) with cesium fluoride at room temperature in THF. While 9 is stable in THF and DME, removal of the solvent leads to the regeneration of stannylene 8. No reaction occurred when 8 was treated with CsF in a hydrocarbon solvent.

1,3-Diazasilabicyclo[1.1.0]butane with a Long Bridging N-N Bond.

A 1,3-diazasilabicyclo[1.1.0]butane (1) is synthesized as thermally stable crystals by using the cycloaddition reaction of an isolable dialkylsilylene with aziadamantane.