88636-32-2Relevant academic research and scientific papers
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 .
