ISSN:0165-0513    

DOI:10.1002/recl.19881070702

出版商:WILEY‐VCH Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractThe possibly reversible addition‐elimination reaction between CH318O−, CD3O−,18O− •and D18O−and various carbonyl‐containing substrates has been studied in the gas phase using Fourier‐Transform Ion‐Cyclotron‐Resonance (FT‐ICR) Mass Spectrometry.Reversible addition‐elimination is observed for the following nucleophile/substrate systems: CH318O−(CD3O−)/RCO2CH3(R = CH3O, C6H5,t‐C4H9),18O− •(H18O−)/CO2and HO−/R′CH18O (R′ = C6H5,t‐C4H9).The results obtained are discussed in relation to

ISSN:0165-0513    

DOI:10.1002/recl.19881070703

出版商:WILEY‐VCH Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractThe structures of adduct ions formed between the nucleophiles HO−and CH3O−and various carbonyl compounds, such as aldehydes, esters and amides, have been probed in the gas phase by studying their proton affinity, collision‐induced dissociation pathways and chemical reactivity, using Fourier‐Transform Ion‐Cyclotron‐Resonance (FT‐ICR) Mass Spectrometry.Most of the generated adduct ions are shown to have stable, often proton‐bound, loosely associated structures as well as stable, covalently bound, tetrahe

ISSN:0165-0513    

DOI:10.1002/recl.19881070704

出版商:WILEY‐VCH Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractLa radioréduction γ de cyclohexanones substituées conduit principalement aux deux cyclohexanols diastéréoisomères correspondants. La stéréosélectivité de cette réaction dépend de la concentration en cétone. L'existence de deux radicaux pyramidaux diastéréoisomères, précurseurs des cyclohexanols, est à l'origine des stéréosélectivités observées. Un processus de solvatation sélective de l'OH radicalaire a été proposé pour rendre compte des variations de stéréosélectivité avec la concentration en cétone.γ Radioreduction of substituted cyclohexanones mainly leads to diastereoisomeric cyclohexanols. The stereoselectivity of radioreduction depends on ketone concentration. The assumption of two pyramidal diastereoisomeric hydroxycyclohexyl radicals explains the observed stereoselectivity. A selective solvation process of the hydroxy group of the radical has been proposed to account for the variations of stereoselec

ISSN:0165-0513    

DOI:10.1002/recl.19881070705

出版商:WILEY‐VCH Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractThe easily accessible benzyl 2,3,4‐tri‐O‐benzyl‐α‐D‐manno‐hexodialdo‐1,5‐pyranoside (2) can be converted, in a highly stereoselective manner, by the two‐step Tamao method to benzyl 2,3,4‐tri‐O‐benzyl‐β‐L‐gly

ISSN:0165-0513    

DOI:10.1002/recl.19881070706

出版商:WILEY‐VCH Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractTwo bichromophoric systems (3 and 4) are studied that contain an electron donor (D) and an electron acceptor (A) moiety interconnected by a fully rigid, saturated hydrocarbon‐bridge. In both the shortest through‐bond pathway from D to A has a length of 8 sigma‐bonds, but whereas this path has an all‐trans configuration in 3, two cis elements have been introduced in 4. Photoinduced, intramolecular electron transfer from D to A occurs more than an order of magnitude faster across the stretched all‐trans bridge in 3 than across the bent bridge in 4 notwithstanding the smaller spatial distance in t

ISSN:0165-0513    

DOI:10.1002/recl.19881070707

出版商:WILEY‐VCH Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractThe preparation of the new chelating ‘HYBRID’ ligand containing secondary amine and tertiary arsine donors HN(CH2CH2AsMe2)2is described. The simple coordination chemistry with [RhCl(COD)]2(COD = cycloocta‐1,5‐diene) and Na2PdCl4to give square planar complexes is also r

ISSN:0165-0513    

DOI:10.1002/recl.19881070708

出版商:WILEY‐VCH Verlag    

年代:1988

数据来源: WILEY

ISSN:0165-0513    

DOI:10.1002/recl.19881070710

出版商:WILEY‐VCH Verlag    

年代:1988

数据来源: WILEY

ISSN:0165-0513    

DOI:10.1002/recl.19881070701

出版商:WILEY‐VCH Verlag    

年代:1988

数据来源: WILEY