5577-67-3Relevant academic research and scientific papers
Synthesis and Structures of New 1,3,2,4-Diphosphadiboretanes
Koelle, Peter,Linti, Gerald,Noeth, Heinrich,Wood, Gary L.,Narula, Chaitanya K.,Paine, Robert T.
, p. 871 - 880 (2007/10/02)
Three methods have been devised to prepare new diphosphadiboretanes: a) Base-induced hydrogen halide elimination from (amino)phosphinoboron halides precursors, b) tris(trimethylsilyl)phosphane elimination from R2N-B2 intermediates prepared in situ from combination of R2N-B(Cl)-P(SiMe3)2 and LiP(SiMe3)2, and organylphosphane elimination from aminobis(organylphosphino)boranes R2N-B(PHR')2.The molecular structures of three new 1,3,2,4-diphosphadiboretanes (3, 4a, 4c) were determined by X-ray diffractometry.These are characterized by a planar four-membered B2P2 ring with the phosphorus substituents in trans positions.Their BP bomnds represent single bond distances.Experimental results are compared with MNDO III calculations which reveal a low barrier (ΔE = 5 kcal/mol) for the dimerization of the boraphosphane H2N-B=PMe to the diphospadiboretane (H2N-BPMe)2.
Reactivity of the Labile Silaethene Me2Si=C(SiMe3)2, Stored as Ph2C=NSiMe3 Adducts
Wiberg, N.,Preiner, G.,Wagner, G.,Koepf, H.
, p. 1062 - 1074 (2007/10/02)
Silaethene Me2Si=C(SiMe3)2 (1), stored as Ph2C=NSiMe3 adducts and regenerated from the adducts at about 100 deg C as a reaction intermediate, combines with reactants a-b (e.g.HO-H, RO-H, RCOO-H, RS-H, RHN-H, Ph2CN-H, RO-SiR3, R2N-SiR3, Ph2CN-SiR3, Cl-GeR3, Cl-SnR3) with insertion into the a-b bond, with a=b (e.g.O=CPh2, Me3SiN=CPh2, CH2=CHOMe, cis-piperylene), a=b=c (e.g.RN=N=N, O=N=N), a=b-c=d (e.g. butadiene, isoprene, trans-piperylene, 2,3-dimethylbutadiene, cyclopentadiene, anthracene, benzophenone, N-trimethylsilylbenzophenoneimine) under -, - as well as -c ycloaddition and with a=b-c-H (e.g. propene, butenes, isoprene, 2,3-dimethylbutadiene, acetone) under ene reaction.According to relative reaction rates, insertion and -cycloadditions seem to proceed in two reaction steps, whereas -cycloadditions and ene reactions with organic dienes and enes obviously are one step reactions.For reactivities cf.Table I. - Key words: Silaethene Me2Si=C(SiMe3)2, Insertions, Cycloadditions, Relative Reactivities
