Synthese von 1,2,5-Azastannaborol-Derivaten aus Schwefeldiimid-Anionen undcis-Stannyl-boryl-alkenen – Röntgenstrukturanalyse von zwei 2,5-Dihydro-1-(imino-λ4-sulfanyliden)-1,2,5-azastannaboratolen (original) (raw)

Synthese von 1,2,5-Azastannaborol-Derivaten aus Schwefeldiimid-Anionen und cis-Stannyl-boryl-alkenen -Rontgenstrukturanalyse von zwei 2,SDihydro-l-(imino-h4-sulfany1iden)-1 ,2,5-azastannaboratolen Synthesis of 1.2,5-Azastannaborole Derivatives from Sulfur Diimide Anions and cis-Stannyl-boryl-alkenes -X-ray Crystallographic Study of Two 2,5-Dihydro-1-(imino-h4-sulfanylidene)-1,2.5-azastannaboratoles (E)-3-(Diethylboryl)-2-(chlorodimethylstannyl)-2-pentene (1) reacts with the sulfur diimide anions 3 [R -NSN-K+, R = tBu (a), Me3Si (b), tBuzP (c)] in a 1: 1 ratio, and with 4 (K+ -NSNpKf) in a 2: 1 ratio, to give various heterocycles. The first products of the reaction between 1 and 3 [2,5-dihydro-1-(imino-h4-sulfanylidene)-l,2,5-azastannaboratoles 5 a, b, c] are isolated at -30°C and characterized by X-ray crystallography. The compounds 5a.b rearrange into the borole derivates 6a,b (with an additional N -Sn coordination) by transfer of an ethyl group from the boron to the sulfur atom. Ethylene is eliminated from compound 6a (not 6b) to give the diaminosulfane derivative 7a. The 2: 1 reaction between 1 and 4 affords an unstable intermediate 8 with a fluxional structure, leading to 9 in which an EtS moiety bridges a borole ring (analogous to 6 but without the additional N -Sn coordination) and a boratole ring (analogous to 5). All compounds are characterized by 'H-, "B-, I3C-, "N-(in part), "Siand "'Sn-NMR spectra.