1.3- Dienes acetylene derivative

Isoxazoles from nitrile oxides and acetylene derivatives—Diene syntheses s, 18, 758 isoxazoles from stable sterically hindered nitrile oxides s. G. Grund-mann and J. M. Dean, J. Org. Ghem. 30, 2809 (1965) reactions with cyanogen di-N-oxide s. G. Grundmann et al., A. 687, 191 (1965)... 

Ebdon and coworkers22 "232 have reported telechelic synthesis by a process that involves copolymerizing butadiene or acetylene derivatives to form polymers with internal unsaturation. Ozonolysis of these polymers yields di-end functional polymers. The a,o>dicarboxy1ic acid telechelic was prepared from poly(S-s tot-B) (Scheme 7.19). Precautions were necessary to stop degradation of the PS chains during ozonolysis. 28 The presence of pendant carboxylic acid groups, formed by ozonolysis of 1,2-diene units, was not reported. 

In the general context of donor/acceptor formulation, the carbonyl derivatives (especially ketones) are utilized as electron acceptors in a wide variety of reactions such as additions with Grignard reagents, alkyl metals, enolates (aldol condensation), hydroxide (Cannizzaro reaction), alkoxides (Meerwein-Pondorff-Verley reduction), thiolates, phenolates, etc. reduction to alcohols with lithium aluminum hydride, sodium borohydride, trialkyltin hydrides, etc. and cyloadditions with electron-rich olefins (Paterno-Buchi reaction), acetylenes, and dienes.46... 

Markl et al.92 have obtained heterocyclohexa-2,5-dienes (51), by cycloaddition of arylphosphines, arylarsines, and dialkylstannanes with acetylene derivatives in the presence of 18-crown-6 and benzene. The technique is superior to the conventional free radical method (benzene, AIBN) or to the method employing a strong base (BuLi, THF, or NH2Na,NH3). 

Reaction of the metal substituted acetylene derivative 328 with diphenylcarbodiimide affords the [2+4] cycloadduct 329 In this unusual reaction diphenylcarbodiimide reacts as the diene, involving one of the aromatic double bonds, and the metal substituted acetylene derivative reacts as the dienophile. 

Hexafluoroacetone azine reacts with two equivalents of terminal olefins (71JCS(C)2404) and with acetylene derivatives (75TL1125), forming 1,5-diazabicy-clo[3.3.0]octenes and l,5-diazabicyclo[3.3.0]octa-2,6-dienes 27, respectively (Scheme 27). The cycloaddition involves two [3 + 2] processes. The structure of azamethineimine is confirmed by X-ray analysis data (74AGE475). 

Dienes from 1,2,3-trienes via reductive carboxylation Synthesis of acetylene derivatives from 1,2,3-trienes Reductive alkylation... 

CM-l,2-Ethylene-l,2-disilanes from acetylene derivs. A soln. of tolan in benzene-d added to 2 eqs. r/5-bis(dimethylphenylsilyl)bis(methyldiphenylphosphine)platinum, and allowed to react at room temp, for 15 min - Z-l,2-bis(dimethylphenylsilyl)-l,2-diphenylethene. Y 79%. F.e. and 1,2-disilylation of unactivated ethylene derivs., also 1,4-disilylation of 1,3-dienes, s. T. Kobayashi et al., Chem. Letters 1989, 467-70. 

Diene synthesis with 5-vinyl-2,3-dihydro-1,4-dioxins Phenolether ring from acetylene derivs. via 2,3,4a,7-tetrahydro-1,4-benzodioxins... 

Intramolecular diene synthesis with acetylene derivs. 

Phosphonic acid esters from chlorophosphites— 1,3-Dienes from acetylene derivatives s. 19, 725... 

Without additional reagents 1,4-Dienes by aiiylie addition of ethylene derivatives to active acetylene derivatives... 

Mercuric acetate/sodium tetrahydridoborate Oxymercuration-demercuration s. 22, 143 improved yields with mercuric trifluoroacetate, Markownikoff monohydration of dienes, s. J. Org. Chem. 37, 1941 (1972) ketones from acetylene derivs. s. G. Chandra, D. Devaprabhakara, and M. S. Muthana, Current Sci. 40, 400 (1971)... 

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