839-23-6Relevant academic research and scientific papers
The intricate assembling of gem-diphenylpropargylic units
Maraval, Valerie,Duhayon, Carine,Coppel, Yannick,Chauvin, Remi
experimental part, p. 5144 - 5156 (2009/08/07)
While optimized procedures for selective propargylic - versus allenic - attack (in particular by alkynylsilanes) have proven to be compatible with many substitution patterns at the propargylic center, the case of diarylpropargyl electrophiles has remained problematic. The intrinsic reactivity of 1,1-diphenylpropargylic alcohols [R-C≡C-C(Ph2)OH (R = TMS, H, Me)] in the presence of various acids (and in the absence of additional nucleophile) has thus been systematically investigated. Whereas the monophenyl analogues [R-C≡C-CH(Ph)OH] afford the expected bis(phenylpropargyl) ethers, the diphenyl versions undergo complex but quite selective processes to afford various structural types: depending on the acid used, a diallene, an allenyne, an indenylallene, an indanone or a condensed tetra- and pentacycles were obtained. When the reactions were conducted in the presence of an alkynylsilane capable of playing the role of a competing nucleophile, the expected propargylic substitution products - dialkynyldiphenylmethanes or their isomers - were never observed. The hitherto unknown simple hydrocarbons diethynyl- and dipropynyl-diphenylmethane could, however, be obtained in low yields through a four-step sequence involving allenylidene- and alkynylruthenium intermediates. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
Reactions of gem-Dihalocyclopropanes with Nucleophilic Agents: Formation of Acetylene Derivatives and Reaction Mechanism
Kostikov,Varakin,Molchanov,Ogloblin
, p. 31 - 35 (2007/10/03)
Heating of gem-dibromocyclopropanes with potassium hydroxide in alcohols yields cyclopropanone acetals and 2-propynyl ethers. The mechanism of formation of these compounds is discussed.
