1-Halo-1-alkynes

More often, the preparation of mono-metallic complexes featuring long poly-ynyl ligands MLn (CsC) R has been accomplished by a sequence of crosscoupling reactions between terminal poly-ynyl complexes and 1-halo alkynes and... 

General methods of preparation for alkenyl and alkynyl halides are listed in Table 14-5. By the alkynyl halides we mean 1-halo-alkynes. One interesting method by which they may be prepared employs 1-alkynes with hypohalites ... 

First attemps to achieve nucleophilic substitutions of halogene in chloro- and bromo-alkynes using protic solvents met invariably with failure. Consequently such reactions were considered as hopelessl, 2). Yet evidence gradually accumulated that 1-halo-alkynes are not inherently inert and the year 1962 was a real breakthrough 1,3 4). Nucleophilic substitutions on an sp carbon became routine with the advent of dipolar aprotic solvents such as DMF, DMSO and HMPT, but their use is not always... 

The chemistry of haloalkynes with low-valent metal complexes has been reviewed.142 Two competing reactions of anionic metal carbonyls [M(CO) ] with halo-alkynes are (i) abstraction of X+ to give MX(CO) and (ii) nucleophilic displacement of X- to give M(C=CX)(CO) and M(CO) 2(ji-C=C). A recent study of reactions of haloalkynes with [M(CO)3Cp ]- (M = Cr, Mo, W Cp = Cp, Cp )] has clarified the reaction conditions, which are determined by the nucleophilicity of the anionic metal carbonyl and the electron-withdrawing power of any substituent on the C=C triple bond. Cross-coupling of the anion with a chloroalkyne is catalyzed by palladium.143... 

COUPLING OF ORGANOMETALLIC ALKYNIDES WITH 1-HALO ALKYNES... 

The synthesis of alkynylpalladium(ii) complexes usually proceeds through oxidative addition of a halo-alkyne or of a terminal alkyne to palladium(O) compounds, or by transmetallation employing main group alkynyl compounds and palladium(ii) halide precursors. Especially, the dialkynylpalladium complexes are of much interest as molecular inorganic materials because of their remarkable phase behavior and nonlinear optical properties. Several accounts and... 

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