88636-30-0Relevant academic research and scientific papers
Organosubstituted 2,5-Dihydro-1,2,5-oxoniasilaboratoles - Characterization and Reactivity
Koester, Roland,Seidel, Guenter,Wrackmeyer, Bernd
, p. 1003 - 1016 (2007/10/02)
The potassium salt of the anions , prepared from the organosubstituted cis-2-boryl-1-silylalkenes 1a-d and KOH, react with the electrophiles R1Hal IV: ClElIV(CH3)3, ElIV = Si, Ge, Sn, Pb> to give the neutral five-membered ring compounds .On heating of 3H or 3Sn either ethyl migration occurs to yield the saturated diasteromers , or elimination of ethane takes place to give the unsaturated compounds .The reaction of 2 with ClPb(CH3)3 leads to 3Pb (11B-NMR), which exclusively form 5 with elimination of C2H5Pb(CH3)3.
Organosubstituted 2,5-Dihydro-1,2,5-phosphasilaboroles - Preparation, Characterization, and Transformations
Koester, Roland,Seidel, Guenter,Mueller, Gerhard,Boese, Roland,Wrackmeyer, Bernd
, p. 1381 - 1392 (2007/10/02)
The dimeric 4,5-diethyl-2,5-dihydro-2,2-dimethyl-3-organo-1-phenyl-1,2,5-phosphasilaboroles are prepared in yields of 70-80percent from the acylic (Z)-2-boryl-1-silylethene derivatives ClB(C2H5)C(C2H5)=CRSi(CH3)2Cl with Li2PC6H5.The solid (1a)2 is the trans isomer with a (PB)2 ring (X-ray analysis). (1a)2 forms the solid γ-Pic-1a with γ-picoline (γ-Pic), with trimethylphosphane (TMP) the easily dissociating TMP-1a. trans-Bis(4,5-diethyl-1,2,5,6-tetrahydro-2,2,3-trimethyl-1-phenyl-1,2,5-phosphasilaborin) (2a)2 (X-ray analysis) is obtained by methylene migration from (1a)2 and methylenetriphenylphosphorane (MTPP). (1a)2 reacts with trimethylamine N-oxide (TMANO) by C6H5P/O-exchange to form (3a) and (3'a), whereas (1a)2 and γ-picoline N-oxide (PNO) give γ-Pic-3a and (C6H5P)n (4; 4', 4'': n = 4-6). (1a)2 and electrophiles react to 1:1 addition compounds (1a-AlCl3; 1a-MeI).The crystalline (5a)2 is prepared by B/Al exchange from (1a)2 and 2. (1a)2 reacts with methanol by ring opening to give the (Z)-2-boryl-1-silylethene derivative CH3OB(C2H5)C(C2H5)=C(CH3)Si(CH3)2OCH3 (6a) and phenylphosphane (7) in high yield. (1a)2 and acetylacetone undergo C6H5P/O exchange giving a mixture of 3a and (Z/E)-4-(phenylphosphino)-3-penten-2-one (8). - The 11B-, 13C-, 29Si-, 31P-NMR data of the dimeric C2SiPB and C2SiPCB rings are compared and discussed together with the data of the unsaturated C2SiElB rings .
Substituted 2,5-Dihydro-1,2,5-oxasilaboroles - Preparation, Complexations, and Ring-Opening
Koester, Roland,Seidel, Guenter,Boese, Roland,Wrackmeyer, Bernd
, p. 597 - 616 (2007/10/02)
The two 4,5-diethyl-2,5-dihydro-2,2-dimethyl-3-organo-1,2,5-oxasilaboroles are prepared from and water via the addition compounds in yields of about 90percent. 2a,b are also obtained directly from 1a,b with acetylacetone or with dry acetic acid. 1b can be prepared from sodium triethylhydroborate (A) via sodium triethyl(3-methyl-3-buten-1-ynyl)borate (B), (Z)-4-(diethylboryl)-2-methyl-3-(trimethylsilyl)-1,3-hexadiene (C), sodium aminodiethylborate (D), 4,5,5-triethyl-2,5-dihydro-3-isopropenyl-2,2-dimethyl-1-sodio-1,2,5-azoniasilaboratole (E), and 4,5-diethyl-2,5-dihydro-3-isopropenyl-2,2-dimethyl-1-sodio-1,2,5-azasilaborole (F).The behaviour of 2a,b towards trimethylphsophane (TMP), γ-picoline (formation of γ-Pic-2a), γ-picoline N-oxide (PNO-2a), trimethylamine N-oxide (2'a, 4, 4'a), methylenetriphenylphosphorane (MTPP-2a), aluminium trichloride (2a-AlCl3), triethylaluminium , trichloroborane (3a), dichloroethylborane (3b), phosphorus pentachloride (3a, 3b), methanol (6a), acetylacetone (5a), propanol (7a, 7c) and towards glacial acetic acid (7a, 9) is described. 5-Chloro-4-ethyl-2,5-dihydro-1,2,2,3-tetramethyl-1,2,5-azasilaborole (1c) is readily obainable from 1a and dichloroethylborane. η4-Complexations of 2b give 10b from (CH3CN)3Cr(CO)3, 11b and 11'b from Fe2(CO)9, 12b from Ru3(CO)12, 13b from C5H5Co(C2H4)2, and 14b from C5H5Rh(C2H4)2 (MS and NMR data).The O-exchange in several reactions was monitored by 17O NMR using 17O-enriched compounds (e.g. 2a*, triethylboroxin*, tetraethyldiboroxane*, water*, methanol*).
2,5-Dihydro-1,2,5-thiasilaboroles - Preparation and Complexations
Koester, Roland,Seidel, Guenter,Boese, Roland,Wrackmeyer, Bernd
, p. 709 - 723 (2007/10/02)
The two 4,5-diethyl-2,5-dihydro-2,2-dimethyl-3-organo-1,2,5-thiasilaboroles are easily prepared from the acyclic compounds ClSi(CH3)2CR=C(C2H5)B(C2H5)Cl with dialkaline metal sulfides M2S (M = Li, Na) or with hexamethyldisilthiane 2S. 1a reacts with aluminium trichloride and with Lewis bases (γ-Pic, PNO, TMP, MTPP) to form 1:1-addition compounds (1a-AlCl3, γ-Pic-1a, PNO-1a, TMP-1a, MTPP-1a). ? Complexes LM-1a or -1b are obtained from 1a or b and ligand-transition metal compounds LML'.The LM-fragments are preferentially η4-complexed with the C=C-B-S grouping , but sometimes also with the C=C-C=C grouping of 1b .The sandwich complexes 7a (X-ray analysis of meso-7a) and 7b are prepared from 2 mol of 1a or b with 1 mol of (cyclododecatriene)nickel. - The BS and SiS bonds of 1a and b are easily protolyzed by hydroxy compounds such as methanol and glacial acid with formation of acyclic compounds (8a, 11a), while with acetylacetone S/O exchange is observed leading to the substituted 2,5-dihydro-1,2,5-oxasilaborol 9a. - The mass spectra, the 1H-, 13C- and heteroatom-NMR data of the new compounds 1 to 7 are discussed in connection with results in earlier contributions to this series.
