Synthesis and Reactivity of 1,2-Bis(chlorodimethylgermyl)carborane and 1,2-Bis(bromodimethylstannyl)carborane

Abstract

The 1,2-bis(chlorogermyl)- (1) and 1,2-bis(bromostannyl)carborane (2) have been prepared by the reaction of dilithio-o-carborane with Me(2)GeCl(2) and Me(2)SnBr(2), respectively. Compounds 1 and 2 are found to be good precursors for the synthesis of a variety of cyclization compounds. The Wurtz-type coupling reaction of 1 and 2 using sodium metal afforded the four-membered digerma compound 3 and five-membered tristanna compound 4, respectively. The salt elimination reactions of 1 and 2 using Li(2)N(t)Bu and Li(2)PC(6)H(5) afforded the cyclic products [structure: see text]. The 1,2-bis(dimethylgermyl)carborane 9 and 1,2-bis(dimethylstannyl)carborane 10 were prepared by the reaction of 1 and 2 with sodium cyanoborohydride. The reactions of 9 and 10 with Pd(PPh(3))(4) afforded the bis(germyl)palladium 12 and bis(stannyl)palladium 13 complexes, respectively.

Tin(IV) Compounds with 2-C6F4PPh2 Substituents and Their Reactivity toward Palladium(0): Formation of Tin–Palladium Complexes via Oxidative Addition

“…Only in the case of complex 6 were the Sn–P couplings resolved enough to be extracted from the spectrum, with the 2 J SnP values being 192 and 1844 Hz arising from the cis - and trans -Sn–Pd–P moieties, respectively. Similar Sn–P couplings (extracted from the 31 P­{ 1 H} NMR spectrum) were observed for [κ 2 -{1,2-(Me 2 Sn) 2 Cab}­Pd­(PPh 3 ) 2 ] [155 Hz (cis) and 1443 Hz (trans)] . For 5 , 6 , and 8 , the 31 P NMR signals due to the P atoms of the bridging μ-2-C 6 F 4 PPh 2 moieties (five-membered-ring systems) appear characteristically downfield ( 5 , 65 ppm; 6 , 69 ppm; 8 , 59 ppm).…”

Preparation and Thermal Reaction of Tetrastannapalladacyclopentane. Sn−Sn Bond Formation and Cleavage

“…The 31 P{ 1 H} NMR signal at δ 24.5 is observed with the typical coupling patterns of bis(stannyl)palladium(II) complexes. 27,32 Reaction of [Pd(PCy 3 ) 2 ] with equimolar H 2 SnPh 2 gave a dipalladium(I) complex with bridging stannyl ligands, [{Pd(PCy 3 )} 2 ( μ-η 2 -HSnPh 2 ) 2 ] (3), in 26% yield (eq 4). An excess amount of H 2 SnPh 2 in the presence of [Pd(PCy 3 ) 2 ] forms 3 together with cyclic oligostannanes (SnPh 2 ) 5 and (SnPh 2 ) 6 ( 119 Sn NMR signals at δ -206.0 and -217.2).…”

Recent developments in homobimetallic reagents and catalysts for organic synthesis

“…Upon reaction with Me 2 GeCl 2 or Me 2 SnBr 2 [15], 1,2-bis(chlorogermyl)carborane or 1,2-bis(bromostannyl)carborane 11 is generated, respectively. These two compounds can be converted into a several cyclic compounds (12 in Scheme 5) [16]. Mercuracarborands were prepared using dilithio carborane and they formed the porous material 13 with a new bonding motif by supramolecular self-assembly [17].…”