41653-95-6Relevant articles and documents
Transition Metal-Catalyzed Intramolecular Cyclization of 1,5- And 1,6-Dienes via Direct Cleavage and Addition of the Carbon-Hydrogen Bond
Fujii, Naoaki,Kakiuchi, Fumitoshi,Yamada, Airi,Chatani, Naoto,Murai, Shinji
, p. 285 - 298 (1998)
Ruthenium- and rhodium-catalyzed intramolecular C-H/olefin coupling reactions of 1-(2-pyridyl)-, 1-(2-imidazolyl-, and 1-(2-oxazolyl)-1,5-dienes proceeded in a regiospecific manner to give 5-membered ring products. Their 1,6-diene analogues are also applicable to the cyclization reaction to give the corresponding 5- and 6-membered carbocycles. For the cyclization of the pyridine derivatives, [RhCl(PPh3)3] showed the highest catalytic activity with respect to efficiency and selectivity. When the imidazole derivatives were employed to the cyclization reaction, the combination of the rhodium(I) complex and the relatively sterically bulky phosphine (e.g., PCy3 and PPFOMe) was a quite effective catalyst system. In the case of the oxazoles, the ruthenium complex, [Ru(H)2(CO)(PPh3)3], showed the highest activity among the catalysts examined. These catalytic reactions usually proceed at 120°C. The [RhCl(PPh3)3]-catalyzed cyclization reaction of 2-[(1E)-4,4-dimethyl-1,5-hexadienyl]pyridine smoothly proceeded even at room temperature to give the corresponding cyclized product in 93% yield after 24 h. A hybrid catalyst system containing the rhodium(I) and both PPh3 and P(o-tolyl)3 had a slightly better catalytic activity compared with that of [RhCl(PPh3)3]. The intramolecular cyclization can be also applied to the C-H/CO/olefin coupling reactions. These carbonylation reactions gave the 5-membered ring ketones exclusively. The intramolecular C-H/olefin coupling reactions provide a new entry for constructing carbocyclic compounds from 1,n-dienes.
Ti-direct, powerful, stereoselective aldol-type additions of esters and thioesters to carbonyl compounds: Application to the synthesis and evaluation of lactone analogs of jasmone perfumes
Nagase, Ryohei,Matsumoto, Noriaki,Hosomi, Kohei,Higashi, Takahiro,Funakoshi, Syunsuke,Misaki, Tomonori,Tanabe, Yoo
, p. 151 - 159 (2008/03/28)
An efficient TiCl4-Et3N or Bu3N-promoted aldol-type addition of phenyl and thiophenyl esters or thioaryl esters with aldehydes and ketones was performed (total 46 examples). The present method is advantageous from atom-economical and cost-effective viewpoints; good to excellent yields, moderate to good syn-selectivity, substrate variations, reagent availability, and simple procedures. Utilizing the present reaction as the key step, an efficient short synthesis of three lactone [2(5H)-furanone] analogs of jasmine perfumes was performed. Among them, the lactone analog of cis-jasmone had a unique perfume property (tabac). The Royal Society of Chemistry.
Penicillin acylase-mediated synthesis of 2-acetyl-1-pyrroline and of 2-propionyl-1-pyrroline, key roast-smelling odorants in food. Inclusion complexes with i-cyclodextrin and their NMR and MS characterization
Favino, Tito Fabrizio,Fronza, Giovanni,Fuganti, Claudio,Fuganti, Daniela,Grasselli, Piero,Mele, Andrea
, p. 8975 - 8979 (2007/10/03)
The synthesis of the strong natural roast odorants 1 and 2 is achieved from the C-6 isomeric alcohols 16 and 21 via the acetylenic C-6 and C-7 amines 8 and 9. Key step in the process is the hydrolysis of the W-phenylacetamides 12 and 13 by means of immobilized penicillin acylase, which affords the l-amino-4,5-diketones 14 and 15, spontaneously ring closing to 1 and 2. These latter compounds form inclusion complexes with/?-cyclodextrin, as demonstrated by NMR measurements in deuterated water and FAB-MS spectra.
