One-pot Synthesis Of Alkyne Amine?Alkyne Phosphine And Researches On The Methodology

Yamines and alkynyl phosphine oxide is a generic term of compounds with a nitrogen or phosphine atom directly connected to the alkyneyl groups. The substituted alkynyl compounds have attracted general attention as valuable organic synthetic precursors, as well for constructions of photovoltaic materials, natural products and biologically active molecules. The nitrogen and phosphine functional groups were able to polarize the triple carbon-carbon bonds, which made the alkynyl groups show better reaction properties with good regio-selectivity and high efficiency. Thus, plenty of documentations have been made for the synthesis of the molecules of great significance. Typically, transformations based on elimination procedures or transition metal catalytic cross coupling protocols were utilized. But the drawbacks or shortcomings still restricted the methodologies for general applications. Therefore, it was still highly called for to develop facile and practical pathways for the formations of the compounds to solve the above-mentioned issues.Under this background, a facile and practical methodology for the formation of the carbon-carbon triple bonds was well-demonstrated from our laboratory, especially for the construction of diverse alkynyl sulfides and alkynyl selenides. Within this context, furture investigations for the synthesis of yamines and alkynyl phosphine oxides were carried out by the same strategy, which was induced by the strong base LiHMDS.Two series of substrates of similar structure were designed after extensive literature investigations:1-aryl-2-((4,5-diphenyl)triazol-2-yl) ethanones and 1-(4-aryl)-2-(diphenylphosphinyl) ethanones. Firstly, reactions berween diaryl acetylenes and sodium azide were conducted for the synthesis of 4,5-diaryl-l,2,3-triazoles, and successive treatment of a-bromoketones gave the corresponding substrates; while alkyl diarylphosphinite reacted with a-bromoketones afforded 1-(4-aryl)-2-(diphenylphosphinyl) ethanones as the starting materials for the one-pot preparation methodology. The yamines and alkynyl phosphines were obtained in moderate to good yields.Following the same strategy, reactions were carried out for the formation of the hetero-atom substituted alkynes as below:under the argon atmosphere, LiHMDS (1.5 eq) was added slowly to a solution of the substrates in THF (10 mL) at -20?, and the mixture was stirred for 60 min. Then ClP(O)(OEt)2 (1.7 eq) was added dropwise and the resulting mixture was warmed up to room temperature and stirred for additional 1 h. The reaction mixture was re-cooled to -20? and then another 3.0 equivalent of LiHMDS (1.0 mol·L-1 in THF/Ethylbenzene) was added to the mixture. After being stirred at -20? for 1 h, the reaction was quenched with aqueous NH4Cl solution and the crude products was subsjected to flash column chromatography to give yamines and alkynyl phosphine oxides. Moreover, the intermediate was successfully isolated and characterized by 1H-NMR,13C-NMR and 31P-NMR for clear structure.The newly developed strategy featured for high efficiency and good functional groups tolerance. Also, the transformation was thought attractive and effective for easy-accessible substrates, simple-manipulation and good groups compatibility for the construction of the hetero-atom substituted alkynes.All the known or unknown compounds involved in the thesis were characterized and confirmed by 1H-NMR,13C-NMR and (or) 31P-NMR combined with HRMS,MS.