55962-04-4Relevant academic research and scientific papers
Photocatalytic nucleophilic addition of alcohols to styrenes in Markovnikov and anti-Markovnikov orientation
Weiser, Martin,Hermann, Sergej,Penner, Alexander,Wagenknecht, Hans-Achim
, p. 568 - 575 (2015/06/08)
The nucleophilic addition of methanol and other alcohols to 1,1-diphenylethylene (1) and styrene (6) into the Markovnikov- and anti-Markovnikov-type products was selectively achieved with 1-(N,N-dimethylamino)pyrene (Py) and 1,7-dicyanoperylene-3,4:9,10-tetracarboxylic acid bisimide (PDI) as photoredox catalysts. The regioselectivity was controlled by the photocatalyst. For the reductive mode towards the Markovnikov-type regioselectivity, Py was applied as photocatalyst and triethylamine as electron shuttle. This approach was also used for intramolecular additions. For the oxidative mode towards the anti-Markovnikov-type regioselectivety, PDI was applied together with Ph-SH as additive. Photocatalytic additions of a variety of alcohols gave the corresponding products in good to excellent yields. The proposed photocatalytic electron transfer mechanism was supported by detection of the PDI radical anion as key intermediate and by comparison of two intramolecular reactions with different electron density. Representative mesoflow reactor experiments allowed to significantly shorten the irradiation times and to use sunlight as "green"light source.
Straightforward reductive esterification of carbonyl compounds with carboxylic acids through tosylhydrazone intermediates
Garcia-Munoz, Angel-Humberto,Tomas-Gamasa, Maria,Perez-Aguilar, M. Carmen,Cuevas-Yanez, Erick,Valdes, Carlos
scheme or table, p. 3925 - 3928 (2012/08/28)
The reaction of carboxylic acids with tosylhydrazones in basic media gives rise to the corresponding esters through an O-H insertion reaction in the in situ generated diazo compound. The process is operationally very simple, catalyst free, and very general with regard to the structure of both coupling partners. In particular, the esterification can be accomplished by employing tosylhydrazones derived from enolizable carbonyl compounds. Considering the ready availability of tosylhydrazones from carbonyl compounds, this reaction can be visualized as a reductive esterification of carbonyl compounds.
Ruthenium NHC catalyzed highly asymmetric hydrogenation of benzofurans
Ortega, Nuria,Urban, Slawomir,Beiring, Bernhard,Glorius, Frank
, p. 1710 - 1713 (2012/04/05)
H2-O-T! Aromatic O-heterocycles are a challenging substrates for asymmetric hydrogenation (H2). An in situ formed chiral N-heterocyclic carbene (NHC) ruthenium complex allows the high yielding, completely regioselective, and highly asymmetric hydrogenation of substituted benzofurans at room Temperature, giving valuable 2,3-dihydrobenzofurans (see scheme). Copyright
Three component reaction of arynes with cyclic ethers and active methines: Synthesis of ω-trichloroalkyl phenyl ethers
Okuma, Kentaro,Fukuzaki, Yuta,Nojima, Akiko,Sou, Ayumi,Hino, Haruna,Matsunaga, Nahoko,Nagahora, Noriyoshi,Shioji, Kosei,Yokomori, Yoshinobu
experimental part, p. 1238 - 1247 (2010/12/20)
Synthesis of ω-chlorinated alkyl phenyl ethers by tandem reaction of arynes with cyclic ethers and active methines was achieved. Reaction of benzenediazonium 2-carboxylate with tetrahydropyran or tetrahydrofuran in refluxing chloroform afforded 6,6,6-trichlorohexyl phenyl ether or 5,5,5-trichloropentyl phenyl ether in 40% and 61% yields, respectively. When dichloroacetonitrile was used as a reactant, 5,5-dichloro-5-cyanopentyl phenyl ether was obtained in 61% yield. While benzenediazonium carboxylate did not react with epoxides, reaction of benzyne derived from 2-(trimethylsilyl)phenyl triflate with epoxides afforded 3,3,3-trichloropropyl phenyl ethers in good yields as isomeric mixtures. The reaction of oxetanes with benzyne was also reported.
Reactivity of functionalized arylcarbenes. 2-Phenylethyl side chains and hetero analogues
Kirmse, Wolfgang,Konrad, Wolfgang,Oezkir, Ismail S.
, p. 9935 - 9964 (2007/10/03)
Phenylcarbenes with -X-CH2Ph and -CH2-X-Ph (X = CH2, O, SiMe2) groups in the ortho position were generated thermally and photolytically from diazo or tosylhydrazone precursors. Stereorandom insertion reactions with β-C-H bonds were observed, pointing to a triplet abstraction-recombination mechanism. Large kinetic and stereochemical deuterium isotope effects support this notion. The ample formation of benzocyclobutenes from 2-CH2-X-Ph substrates is due to insertion of the carbenes into ArCH2-X bonds. Addition to the terminal phenyl groups competes with C-H and C-X insertion. The results of benzophenone sensitization and of trapping with methanol suggest that the intramolecular reactions of functionalized arylcarbenes proceed, at best, competitively with spin inversion.
A regioselective lithiation of ortho-cresols using the bis(dimethylamino)phosphoryl group as a directing group: General synthesis of 2,3-dihydrobenzo[b]furans including naturally occurring neolignans
Watanabe,Kawanishi,Akiyoshi,Furukawa
, p. 3123 - 3131 (2007/10/02)
A general synthetic method was developed for 2-aryl-2,3-dihydrobenzo[b]furans via regioselective lithiation of ortho-tolyl tetramethylphosphorodiamidates followed by addition of aromatic aldehydes as a key step. ortho-Tolyl tetramethylphosphorodiamidates
Cyclization of 2'-Bromodeoxybenzoins: A New Synthesis of 2-Phenylbenzofurans
Grimshaw, James,Thompson, Norris
, p. 240 - 241 (2007/10/02)
Reaction of 2'-bromodeoxybenzoins with copper powder in refluxing dimethylacetamide gives the corresponding 2-phenylfuran in good yields.
