摘要:

AbstractThe reaction of new phosphorus dialdehydes PhP(O)‐[(CH2)nCHCHC6H4CHO]2(4a–c,5a) (n= 0:4,n= 1:5;a:para,b:meta,c:ortho), with thiophosphonic bis(hydrazide) PhP(S)[NMeNH2]2(6) yields macrocyclic compounds9b′,c′,10a′,9a″,b″,c″,10a″ and9c′″, arising from the cyclocondensation of one, two, or three equivalents of each reagent, respectively. Molecular modeling of4a‐c,5a, 6and of the intermediate monocondensation products7a‐c,8awas carried out and points out the importance of the geometry of the starting reagents in the competition between inter‐ and in

ISSN:0009-2940    

DOI:10.1002/cber.19951280502

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY

摘要:

AbstractNovel chiral salen‐ or salphen‐type ligands with stereogenic centres in the 1,3‐dicarbonyl moiety2as well as in the amino bridge in15–18were synthesized from the enantiomerically pure Hajos‐Wieche

ISSN:0009-2940    

DOI:10.1002/cber.19951280503

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY

摘要:

AbstractThe strontium and barium tetrahydridoborate complexes M(BH4)2· 2 diglyme and M(BH4)2· 18‐crown‐6 (M = Sr, Ba) have been prepared from the solvates M(BH4)2· 2 THF by ligand displacement.11B‐NMR and IR data reveal strongly polar bonding of the BH4groups to the metal centers, and X‐ray structural analyses of the diglyme and crown ether compounds show molecular units in which the BH4group is in contact via three H atoms with the metal center. In contrast, M(BH4)2· 2 THF compounds are chain polymers in the solid state, and each metal center is surrounded by 2 THF molecules intransposition and four BH4−groups each of which forms bridges with two metal centers. Estimations of the effective radius for the BH4group indicate a high polarity for the M

ISSN:0009-2940    

DOI:10.1002/cber.19951280504

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY

摘要:

AbstractThe geometric structure and conformational properties of bis(trifluoromethylthio)methane, CH2(SCF3)2' were determined by gas electron diffraction. The main conformer (70 ± 15%) possessesC2symmetry with dihedral angles Φ(SCSC) = 79.1(10)°. The second conformer possessesC1symmetry. The following skeletal geometric parameters (distancesra[pm] and angles 〈α[°] with 3‐σ uncertainties) were obtained: CS 183.6(3), SCF3, 179.3(3), SCS 112.1(6), and CSC 98.2(10). The geometric structures and relative conformational stabilities were well reproduced by ab initio calculations a

ISSN:0009-2940    

DOI:10.1002/cber.19951280505

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY

摘要:

AbstractThermally and air‐stable β‐phosphaenones were synthesized by functionalization of Mes*PCCl2(1; Mes* = supermesityl = 2,4,6‐tri‐tert‐butylphenyl). At low temperature,1was lithiated by halogen‐metal exchange withn‐butyllithium to give the phosphanylidene carbenoid (Z)‐Mes*PC(Cl)Li [(Z)‐2] which reacted with acid chlorides to furnish theC‐carbonyl‐substituted phosphaalkenes (Z)‐Mes*PC(Cl)R (3: P = COtBu;4: R = COPh;5: R = COOEt). The reaction of (Z)‐2with carbon dioxide furnished the carboxylate6, which was converted by treatment with pivaloyl chloride or trimethylsilyl chloride into the phosphaalkenes7and8functionalized at the carbon atom by an anhydride or a trimethylsilyl ester function, respectively. Acidification of6or hydrolysis of8with water in chloroform solution afforded the novel carboxylic acid (Z)‐Mes*PC(Cl)COOH (9). Spectroscopic investigations (NMR, UV, IR) of3–9and the X‐ray structures of3and4are presented. Based on these properties and on theoretical calculations, the occurrence of conjugation in the β‐phosphaenone system is discussed and compared with

ISSN:0009-2940    

DOI:10.1002/cber.19951280506

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY

摘要:

AbstractNew preparations for the following compounds are described: Te(SCF3)2, Te(NSO)2, and Cl2Te(NSO)2. The catalytic or thermal SO2elimination from Cl2Te(NSO)2affords a coordinated or non‐coordinated thiachalcogenadiazole. Conversions of these compounds are reported. Evidence for the proposed mechanism for the reaction between Te(NSO)2and SbCl5is provided. Cl4Te2N2(SCF3)2, prepared from TeCl4and CF3SN(SiMe3)2, reacts with LiN(SiMe3)2to form [(Me3Si)2N]4Te2N2(SCF3)2. An X‐ray structural analysis of Cl4Te2N2(SCF3)2is presen

ISSN:0009-2940    

DOI:10.1002/cber.19951280507

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY

摘要:

AbstractLithiated 2‐methylpyridine reacts with 2,3,4,5‐tetramethylfulvene (TMF) to give 2‐[2‐(2,3,4,5‐tetramethylcyclopenta‐1,4‐dien‐1‐yl)ethyl]pyridine (2H) after aqueous work‐up. Similarly, a mixture of 2‐methyl‐6‐[2‐(2,3,4,5‐tetramethylcyclopenta‐1,4‐dien‐1‐yl)ethyl]pyridine (3H) and 2,6‐bis[2‐(2,3,4,5‐tetramethylcyclopenta‐1,4‐dien‐1‐yl)ethyl]pyridine (4H2) was obtained from monolithiated 2,6‐dimethylpyridine and TMF. All three compounds were obtained as a roughly statistical mixture of double‐bond isomers. 2‐Lithiopyridine reacts with 2,3,4,5‐tetramethylcyclopent‐2‐enone to yield 2‐(2,3,4,5‐tetramethylcyclopenta‐1,3‐dien‐1‐yl)pyridine (5H) after acidic work‐up. This compound was obtained as a non‐statistical mixture of double‐bond isomers, which is presumably due to intramolecular hydrogen‐bond interactions. The lithiated derivatives2Li,3Li and5Li react with iron(II) chloride to afford the respective ferrocenes (2)2Fe (8), (3)2Fe (9) and (5)2Fe (10). The structure of10was determined by a single‐crystal X‐ray diffraction study. The cyclopentadienyl ligands adopt a staggered conformation; the pyridyl rings are arranged in a stacked fashion with the closest ring‐ring contact being 3.1

ISSN:0009-2940    

DOI:10.1002/cber.19951280508

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY

摘要:

AbstractReaction of 2,2‐Dimethyl‐N‐lithio‐1,3‐bis[(trimethylsilyl)amino]propane (4a) with RGaBr2(R = Br, Mes) allows the isolation of the cyclic monomeric amine(amino)gallanes5and6. The cyclic bis(amino) gallanes7and9as well as the indium homologue10were obtained by reaction of gallium halides RGaCl2(R = Cl, Mes) or InCl3with dilithiated4. In the case of R = Mes the product is a monomer. In addition, the tetrakis(amino)gallate8was isolated. Single‐crystal X‐ray diffraction studies confirmed the constitutions. Compound5has one short GaN single bond (184 pm) and a longer GaN dative bond (204 pm). Compound7exhibits a central asymmetrical four‐membered Ga2N2ring [d(GaN) = 199.4, 205.6 pm] withsyn‐oriented substituents. The terminal GaN bond length is 184.3 pm. Two nitrogen atoms bridge the lithium and gallium atom in the gallate8[d(LiN) = 206 pm]. Two Li‐H contacts complete the coordinati

ISSN:0009-2940    

DOI:10.1002/cber.19951280509

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY

摘要:

AbstractThe reaction of LiAr (Ar = 2‐[(dimethylamino)methyl]phenyl) with AlCl3, MeAlCl2, and Me2AlCl in a 1:1 ratio yields the corresponding organoaluminium compounds ArAlCl2, ArAl(Cl)Me, and ArAlMe2(1–3). The alanes Ar2AlCl and Ar2AlMe (4and5) were synthesized from AlCl3and MeAlCl2with two equivalents of LiAr. The products ArAl(Cl)R [R =tBu, C(SiMe3)3]6and7are formed by the reaction of LiR with1. The Lewis acid1adds the basesiPrNH2and THF to yield the adducts1·iPrNH2and1· THF. The structures of the products were deduced from the1H‐,13C‐, and27Al‐NMR spectra and were confirmed by X‐ray structural determinations o

ISSN:0009-2940    

DOI:10.1002/cber.19951280510

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY

摘要:

AbstractThe dimethylamino‐substituted phosphaalkene1reacts with hexafluoroacetone (HFA) with addition at the PC bond to form the 1,5,2‐dioxaphosphorinane2. The structure of2was confirmed by an X‐ray crystal structure analysis. The six‐membered ring displays an envelope conformation with the phosphorus atom out of the plane, but the phosphorus is disordered over two sites. Reaction ofP‐trimethylsilyl‐substituted phosphaalkenes with HFA proceeds with retention of the PC double bond and insertion of HFA into the PSi bond. Two isomeric products are obtained and are characterized by1H‐,13C‐,19F‐, and31P‐NMR spectroscopy, IR spectroscopy, mass spectrometr

ISSN:0009-2940    

DOI:10.1002/cber.19951280511

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY