33415-80-4Relevant academic research and scientific papers
Ligand-Free Catalytic Cross-Coupling in the System Aryl Halide–Arylacetylene–Alkene
Lagoda,Vidyaeva,Larina,Kurokhtina,Schmidt
, p. 71 - 78 (2021/03/03)
Abstract: Three-component cross-coupling in the system aryl halide–arylacetylene–alkenein the presence of simplest ligand-free palladium catalysts gave products ofboth 1+1+1-coupling and cross-dimerization of arylacetylene with alkene. Thepossibility of c
Efficient hydroarylation of terminal alkynes with sodium tetraphenylborate performed in water under mild conditions
Koci?cka,Trzeciak
, (2019/11/02)
The hydroarylation of terminal alkynes with sodium tetraphenylborate was performed in high yield within 3 h at room temperature in water, using palladium(II) complexes with imidazole ligands as catalysts. Under these conditions, differently substituted phenylacetylene substrates were converted to arylalkenes and aryl-substituted dienes. High conversion and excellent selectivity were achieved in the hydroarylation of alkynols with sodium tetraphenylborate. Only one product, arylalkene with an OH group, was formed in these reactions with the yield dependent on the kind of alkynol used. A plausible hydroarylation reaction mechanism was proposed on the basis of the palladium species identified in the reaction mixture and H/D exchange studies. The contribution of water as the hydride source was evidenced.
Hydrothermal photochemistry as a mechanistic tool in organic geochemistry: The chemistry of dibenzyl ketone
Yang, Ziming,Lorance, Edward D.,Bockisch, Christiana,Williams, Lynda B.,Hartnett, Hilairy E.,Shock, Everett L.,Gould, Ian R.
, p. 7861 - 7871 (2015/03/18)
Hydrothermal organic transformations under geochemically relevant conditions can result in complex product mixtures that form via multiple reaction pathways. The hydrothermal decomposition reactions of the model ketone dibenzyl ketone form a mixture of reduction, dehydration, fragmentation, and coupling products that suggest simultaneous and competitive radical and ionic reaction pathways. Here we show how Norrish Type I photocleavage of dibenzyl ketone can be used to independently generate the benzyl radicals previously proposed as the primary intermediates for the pure hydrothermal reaction. Under hydrothermal conditions, the benzyl radicals undergo hydrogen atom abstraction from dibenzyl ketone and para-coupling reactions that are not observed under ambient conditions. The photochemical method allows the primary radical coupling products to be identified, and because these products are generated rapidly, the method also allows the kinetics of the subsequent dehydration and Paal-Knorr cyclization reactions to be measured. In this way, the radical and ionic thermal and hydrothermal reaction pathways can be studied separately.
Reactive alkyne complexes of tantalum and their metallacyclization chemistry: Models for alkyne cyclotrimerization by the early transition metals
Strickler, Jamie R.,Wexler, Pamela A.,Wigley, David E.
, p. 2067 - 2069 (2008/10/08)
The reduction of Ta(DIPP)3Cl2 (DIPP = 2,6-diisopropylphenoxide) in the presence of bulky alkynes RC≡CR′ (R = R′ = Ph; R = Me3Si, R′ = Me) provides the alkyne adducts (DIPP)3Ta(RC≡CR′) in high yield. Unlike all previously known tantalum alkyne complexes, (DIPP)3Ta(PhC≡CPh) readily undergoes metallacyclization reactions with smaller alkynes RC≡CR′ (R = R′ = Me or Et) and terminal alkynes RC≡CR′ (R = CMe3, SiMe3, or Ph; R′ = H) to form the tantalacyclopentadienes (DIPP)3Ta(CPh=CPhCR′=CR). The molecular structure of the related metallacyclic complex (DIPP)3Ta(CEt=CEtCEt=CEt) has been determined. This compound crystallizes in the monoclinic space group P21/n [No. 14] with a = 14.340 (15) ?, b = 16.322 (22) ?, c = 19.929 (11) ?, β = 94.05 (7)°, V = 4655.9 ?3, and ρ(calcd) = 1.25 g cm-3 for mol wt 877.05 and Z = 4. Structure solution and refinement included 3191 reflections with Fo2 > 3.0σ(Fo2) of 9088 total (8245 unique) reflections measured for final discrepancy indices of RF = 4.6% and RwF = 4.5%. The molecular structure reveals a severely crowded coordination sphere, which is consistent with the fact that alkyne cyclotrimerization does not proceed beyond this point. By using the less crowded precursor Ta(DIPP)2Cl3 and decreasing the alkyne size from Me3SiC≡CSiMe3 to PhC≡CPh to MeC≡ CMe, successively higher coordinated alkyne cyclooligomers (C2, C4, and C6 compounds, respectively) can be isolated.
