The iridium(I) complex [Ir(CO2Me)(CO)2(PPh3)2] undergoes a transesterification reaction with the alcohols CH2C(R)CH2OH (R = H, Me), MeCCCH2CH2OH, and HOCH2CH2OH to afford the complexes [Ir(CO2CH2CH2CMe)(CO)2(PPh3)2] and [Ir(CO2CH2CH2OH)(CO)2(PPh3)2], respectively. In contrast the acetylenic alcohol HCCCH2CH2OH gives [Ir(CCCH2CH2OH)(CO)PPh3)2]. Some reactions of the new complexes are described. 相似文献
β-ketonitriles R1COCH2CN and R1COCH(R2)CN are respectively prepared from (CH3)3SiOCOCHLiCN or R2CHLiCN by acylation reaction with mixed anhydrides RCOOCO2Et. 相似文献
The Significance of electrostatic effects on the origin of π-facial stereoselectivity in nucleophilic additions to β,γ-unsaturated carbonyl systems was shown through theoretical studies (ab initio MO calculations of transition structures for NaH + HCOCH2CCH) and experimental results (M(BH4)n reduction of PhCOCH(CH3)R (M Na, Zn, Cd; R C2H5, CHCH2, CCH)). 相似文献
A general procedure, giving high yields for the synthesis of (Ph3P)2Pt(CCR)2 complexes (R = C6H5, C(CH2)CH3, (CH2)6CCH, CH2OH, CH(OH)CH3, CH(OH)C6H5, CH2CH(OH)CH3, C(OH)(CH3)CH3, C6H10OH, C(OH)(CH3)CH2CH3, CH2NHCH3, CH2NHCH2C6H5, CH2N(CH3)2, CH2N(C2H5)2) is reported. On the basis of the low frequency IR spectra a trans structure is proposed for all complexes. UV spectra are also reported. 相似文献
3,4-Pentadienol was protected with ethyl vinyl ether and regioselectively (70%) deprotonated at the terminal position by treatment with BuLi in THF at low temperature. Starting from the so obtained lithium compound, Marasin (nona-6,8-diyne-3,4-dienol) (1a) and 9-Me-Marasin (deca-6,8-diyne-3,4-dienol) (1b) were prepared by two metal-mediated synthetic routes. Route A involves transmetallation of the lithium compound with LiCuBr2, followed by reaction with Me3Si-CC-CC-l or Me-CC-CC-l. Route B involves transmetallation with ZnCl2, followed by a palladium-catalyzed coupling reaction with Me3Si-CC-CC-Br or Me-CC-CC-Br. Before removal of the protecting groups the yield of C-C coupled products, Me3Si-CC-CC-CHCCH-CH2CH2OCH(Me)OEt and Me-CC-CC-CHCCH-CH2CH2-OCH(Me)OEt (6a and 6b) was 95 % via route A. Route B afforded (6a) and for (6b) in 75% and 50 % yield, respectively. After removal of the trimethylsilyl group with AgNO3 and the acetal group with trace of acid, (1a) and (1b) were obtained by route A in 20 % and 65 % overall yield, respectively, and by route B in 13 % and 30 % overall yield, respectively. The antibiotic activity of both compounds was tested against Staphylococcus aureus and the MIC (Minimal Inhibiting Concentration) for Marasin was 0.2 (fesol|μg/ml) 9-Me-marasin was not active suggesting that the free acetylene function of the allenediyne is essential for the antibiotic activity. 相似文献
13C, 29Si and 119Sn NMR data (chemical shifts and coupling constants) are reported for 1,3-diynes RCCCCR′ (R = R′ = H, t-C4H9, Si(CH3)3, Sn(CH3)3; R = Si(CH3)3, R′ = Sn(CH3)3). The data are in agreement with an increased polarity of the SnC bond in the 1,3-diynes as compared with alkynylstannanes. 相似文献
The reaction of (CH3)3SnCCCCSn(CH3)3 with B(C2H5)3 is complex. With B(i-C3H7)3 it is shown unambiguously that the reaction proceeds via an enyne intermediate which has been identified by 1H, 11B, 13C and 119Sn NMR spectroscopy. 相似文献
The rotational barriers in dimethyl acetylene (CH3CCCH3), diamino acetylene (H2NCCNH2), dihydroxy acetylene (HOCCOH), methyl trifluoro methyl acetylene (CF3CCCH3), silyl methyl acetylene (SiH3CCH3), propene, cis and trans 2-butene and ethane were studied by ab initio molecular orbital methods using various basis sets. The eclipsed structure for dimethyl acetylene and its CF3 and SiH3 analogs was found to be the most stable, as has been inferred from experimental work, and the barrier height for these compounds has been predicted. The barriers in the OH and NH2 substituted acetylenes, propene, butene and ethane were studied in order to more clearly understand the important influences in determining the barrier mechanism; specifically, the delocalized molecular orbital and Pauling VB model have been compared. 相似文献
The preparation of the compounds o-C6H4(CCMR3)2 (M = Si, Ge, Pb; R = CH3; M = Pb; R = C6H5) is described. Their properties are compared with those of o-C6H4(CCSnR3)2 (R = CH3, C6H5) and those of their p-isomers. The structures and bonding conditions proposed for these molecules are supported by dipole measurements, mass spectroscopy, IR, Raman, 1H NMR and 13C NMR data. 相似文献
One-electron oxidation and one-electron reduction of the electron-rich acetylene derivative, hexakis(trimethylsilyl)-2-butyne [H3C3)3Si]3CCCC[Si(CH3)3]3, unexpectedly produce the persistent radical cation and radical anion of the hitherto unknown neutral compound, tetrakis(trimethylsilyl)butatriene (R3Si)2CCCC(SiR3)2. The radical anion can also be generated from the corresponding diacetylene, bis(trimethylsilyl)-1,3-butadiyne R3SiCCCCSiR3 and potassium metal, obviously via disproportionation. Photoelectron and electron spin resonance spectroscopic data permit the detection and characterization of the individual species. The stability of both the radical anion and the radical cation of the same molecule can be rationalized by the unique combination of the twofold butatriene π-system with 4 R3Si substituents, which can act either as electron donors or electron acceptors and thus stabilize the ground state of either the cation or the anion. 相似文献
A number of α-β acetylenic carbinols RFCCC(OH)RR′, in which the acetylenic proton was substituted by a F-alkyl group, were first prepared, from a classical reaction of (F-alkynyl)- lithium derivatives RFCCLi upon various carbonyl compounds.On another hand, the reaction of propargyl bromide metallic complexes (organoaluminic, or ultrasonic irradiation activated organozinc) upon some polyfluorinated ketones RFCOR led to the formation, in convenient yields, of the propargylic carbinols HCCCH2C(OH)RRF.The synthesis and properties of these series of new (F-alkyl) substituted acetylenic and propargylic alcohols are described and discussed. 相似文献
Chemical shifts δ(13C), δ(119Sn) and coupling constants J(119Sn13C) for alkynylstannanes of the type R4-nSn(CCR′)n (n = 1–4) are reported. The values of 1J(119Sn13C) and 2J(119SnC13C) depend upon the nature of the substituent R′. 1J(119Sn13C) in Sn(CCCH3)4 is 1168 Hz, much larger than a value predicted in the literature of ca. 700 Hz. The comparison of δ(119Sn) for (CH3)2Sn(CCR′)2 and 1,1,4,4-tetramethyl-1-stannacyclohexadi-2,5-ene suggests that the δ(119Sn) of alkynylstannanes are determined only to a small extent by the diamagnetic anisotropic effect of the CC-triple bond. 相似文献
Normal coordinate calculations have been made for the actual conformers of the molecules CH2C(CH3)CH2X, XCN, Br. A valence force field of 37(34) force constants reproduced the 33(30) fundamental frequencies for XCN(Br) to an average deviation of 14(11) cm−1. For 3-bromo-2-methyl-1-propene the calculation suggests a reassignment. According to this, the existing experimental data may be reinterpreted as 3-bromo-2-methyl-1-propene having 2 conformers, instead of 3 as suggested earlier. 相似文献
A cationic complex, trans-[(mesityl)Ni(PPhMe2)2(NCMe)]ClO4 (IIa), has been prepared rom trans-(mesityl)Ni(PPhMe2)2Br and silver perchlorate in acetone/acetonitrile. IIa reacts with several neutral ligands to give trans-[(mesityl)Ni(PPhMe2)2L]ClO4 (L = 2-pic, 3-pic, 3,4-lut, 2,5-lut, methyl isonicotinate, N-ethyl imidazole, PPhMe2, P(Ome)3), with halide anions to give trans-(mesityl)Ni(PPhMe2)2X (X = Cl, NNN), and with terminal alkynes in the presence of triethylamine to give trans-(mesityl)Ni(PPhMe2)2CCR (R = H, Me, CH2CH2Oh, Ph, C6H4OMe-p). Some related alkynyl complexes trans-CCl2CClNi(PPhMe2)2CCR (R = H, Me, Ph, C6H4OMe-p) and trans-{(o-MeO)2C6H3}Ni(PPhMe2)2CCr (R = H, Ph) also have been prepared from the corresponding trans-R′Ni(PPhMe2)2Cl, silver perchlorate and HCCR in acetonitrile-triethylamine. trans-(Mesityl)Ni(PPhMe2)2CCH reacts with methanol in the presence of perchloric acid to give a cationic carbne complex, trans-[(mesityl)Ni(PPhMe2)2{C(OMe)Me}]ClO4. 相似文献
Addition at low temperatures of carbon disulfide to a solution of the lithium compound (R1 = CH3, C3H7, Ph, OCH3, SCH3) results in the initial formation of an allenic carbodithioate H2CCC(R1)CSSLi, while for R1 = t-C4H9 or SiMe3 acetylenic carbodithioates R1CCCH2CSSLi are formed. The initial products undergo very rapid subsequent reactions. For R1 = CH3 or C3H7 the lithium compound adds (in the allenic form) in a conjugated fashion to the CCCS system of the allenic carbodithioate. The acetylenic dithioates are deprotonated to give the geminal dithiolates R1CCCHC(SLi)2. For R1 = Ph, OCH3 or SCH3, subsequent deprotonation at the terminal carbon atom of the initial allenic dithioate gives enyne dithiolates HCCC(R1)C(SCH3)2; this reaction proceeds more satisfactorily with the potassium compounds. 相似文献
Interaction of NaCo(dmg)2py with (R)2CC(OSO2CF3)CCH in methanol provides a simple route to novel, stable cumulenyl complexes (R)2CCCCHCo(dmg)2py, where R = CH3 or C6H5. In the case of R = H the stable ene-yne complex H2CC(CCH)Co(dmg)2py was isolated. The formation and properties of these complexes are discussed. 相似文献
The complexes trans-[Ru(PMe3)4(CCPh)2] and trans-[Ru(PMe3)4(CCC6H4C6H4CCSnMe3)2] have been prepared from the reaction between trans-[Ru(PMe3)4Cl2] and an excess of either Me3SnCCPh or Me3SnCCRCCSnMe3 (R = p-C6H4C6H4), respectively. However, if only one equivalent of the latter reagent is used the rod-like polymeric species trans-[-Ru(PMe3)4CCRCC-]n can be isolated. 相似文献
The diphosphinoalkyne Ph2PCCPPh2 (2) reacts with the μ-alkylidene complex (CO)9W2[CHCHC(CH3)2] (1) to give, upon insertion of the alkyne into one of the CW bonds of the bridging carbene followed by rupture of a CP bond, a phosphido complex (CO)8W2[C(PPh2)CCHCHC(CH3)2] PPh2 (3). An unexpected long-range 1H31P coupling, through five bonds, is observed in complex 3. 相似文献
The interaction of C5H5Fe(CO)2I with (+)-α-methylbenzyl isocyanide yields the diastereoisomeric pair (+)- and (−)-C5H5Fe(CO)[CN-CH(CH3)- (C6H5)]I. The two diastereoisomers can be separated on the basis of their different solubilities by repeated precipitation from methylene chloride/pentane. Excluding light the complexes are configurationally stable in the solid state as well as in solution. In daylight, however, the optical rotations decrease rapidly (photoracemisation). The ORD and CD spectra (+)- and (−)-C5H5Fe(CO)[CN-CH(CH3)(C6H5)]I show pronounced Cotton effects. 相似文献