806-71-3Relevant articles and documents
Synthesis of indenes via Bronsted acid catalyzed cyclization of diaryl- and alkyl aryl-1,3-dienes
Eom, Dahan,Park, Sangjune,Park, Youngchul,Ryu, Taekyu,Lee, Phil Ho
supporting information, p. 5392 - 5395,4 (2012/12/12)
Substituted indenes can be synthesized via the Bronsted acid catalyzed cyclization of diaryl- and alkyl aryl-1,3-dienes. In this approach, treatment of symmetric or unsymmetric diaryl- and alkyl aryl-1,3-dienes with a catalytic amount of trifluoromethanesulfonic acid gives a variety of indene derivatives in good to excellent yields under mild conditions.
Birch reductions at room temperature with alkali metals in silica gel (Na2K-SG(I))
Nandi, Partha,Dye, James L.,Jackson, James E.
body text, p. 5790 - 5792 (2010/01/06)
(Chemical Equation Presented) Alkali metals in silica gel (the Na 2K-SG(I) reagent) cleanly effect Birch reductions of substrates with at least two or more aromatic rings. The reaction conditions are alcohol-free, ammonia-free, and achieve excellent yields and high selectivities at room temperature.
Mechanistic comparison of the nickel(0)-catalyzed homo-oligomerization and co-oligomerization of alkynes and nitriles
Eisch, John J.,Ma, Xin,Han, Kyoung I.,Gitua, John N.,Krüger, Carl
, p. 77 - 88 (2007/10/03)
A comparative mechanistic study of the nickel(0)-catalyzed homo-oligomerization and co-oligomerization of alkynes and of nitriles has been undertaken, with diphenylacetylene and benzonitrile, towards an array of nickel(0) reagents, such as finely divided nickel, (COD)2Ni, (Bpy)(COD)Ni, (Et3P)4Ni, (Bpy)(PhC≡CPh)Ni and (COD)2Ni-MeAlCl2 combinations in donor (THF) and nondonor (PhMe or neat substrate) solvents. Special attention has been given to the detailed molecular structures of the initial 1:1 adducts, (Bpy)(PhC≡CPh)Ni, (Ph3P)3(PhC≡CPh)Ni and [(Ph3P)(PhC≡N)Ni]4 by a consideration of XRD and IR data. Data from the single crystal XRD analysis of (Bpy)(PhC≡CPh)Ni, reported here for the first time, are shown to be in excellent accord with the presence of a 2,3-diphenylnickelacyclopropene ring for the (PhC≡CPh)Ni moiety with almost coplanar chelating coordination of the bipyridyl ligand, rather than with the presence of simple "side-on" coordination of the alkyne with the metal center. A parallel analysis of XRD and IR data for the two benzonitrile-nickel(0) complexes, which were drawn from previous publications, has concluded that the nickel in (Ph3P)3(PhC≡N)Ni is coordinated in an "end-on" fashion and the nickel centers in [(Ph3P)(PhC≡N)Ni]4 are coordinated as bridges between nitrile units in both an "end-on" and "side-on" manner. The stereochemistry of the acid hydrolysis of the nickelacyclopropene complex to (E)- or (Z)-alkene was shown to depend on the structure of the cleaving acid; parallel hydrolysis of nitrile-nickel complexes has shown that "end- on" complexes regenerate the nitrile, while "side-on" complexes lead to the aldehyde. In homo-oligomerization of diphenylacetylene or other alkyne the clean cyclotrimerization to the benzene derivative was shown to proceed by way of a nickelacyclopentadiene intermediate, as was evident by chemical trapping. The homo-oligomerization of benzonitrile by nickel(0) was found not to lead to 2,4,6-triphenyl-1,3,5-triazine, as claimed in the literature, but rather solely to benzyl phenyl ketone, the dimeric hydrolysis product. The attempted co-oligomerization of diphenylacetylene and benzonitrile with ordinary nickel(0) complexes led only to the homocyclotrimer of the alkyne. Only when the alkyne was prebonded to the nickel, as in (Bpy)(PhC≡N)Ni, could significant amounts of a codimerization product with the nitrile be observed. The origin of the triazine, claimed in a previous report to form from benzonitrile and Raney nickel, has been traced to the presence of adventitious moisture and air. Other unexpected products formed from nickel(0) complexes and benzonitrile have been shown to arise from oxidative addition reactions of nickel(0) with various σ C-E bonds.
