22717-95-9Relevant articles and documents
Selective Borylation of [4]Helicene
Ne?as, David,Kaiser, Reinhard P.,Ul?, Jan
, p. 5647 - 5652 (2016/12/14)
The Ir-catalyzed borylation of [4]helicene under different reaction conditions was studied for the first time. The results indicate that monoborylation proceeds to give a mixture of 2- and 3-borylated products in good yields (up to 74 % isolated yield). It was possible to shift the selectivity in favor of the 3-borylated product by using sterically demanding ligands. The monoborylated [4]helicenes were further arylated by using a Suzuki–Miyaura cross-coupling or oxidized to the corresponding phenols in very good yields.
Exploiting the π-acceptor properties of carbene-stabilized phosphorus centered trications [L3P] 3+: Applications in Pt(II) catalysis
Carreras, Javier,Patil, Mahendra,Thiel, Walter,Alcarazo, Manuel
supporting information, p. 16753 - 16758,6 (2012/12/13)
Reaction of tris(dimethylaminocyclopropenium) substituted phosphine 1 with K2PtCl4 afforded the bench stable complex 3 which upon treatment with Ag[CB11H6Cl6] turned out to be an excellent catalyst for the transformation of a variety of ortho-biaryl substituted alkynes into polycyclic homo- and heteroarenes of different size, shape, and curvature through a 6-endo-dig cyclization. This constitutes the first example ever reported of using a P1-centered trication as ligand in catalysis. The strong π-acceptor character of 1 that derives from its three positive charges substantially increases the intrinsic π-acidity of Pt in complex 1?PtCl2 and dramatically enhances its ability to activate π-systems toward nucleophilic attack. As a consequence, a remarkable acceleration of the model transformation is observed when compared with other classical π-acceptor ligands such as P(OPh)3 or P(C 6F5)3. Moreover, the employment of 1 as ligand also expands the scope of this reaction to previously inaccessible substitution patterns. Kinetic studies and deuterium labeling experiments as well as density functional theory (DFT) calculations were performed in order to explain these findings.
Intramolecular gold(III) catalysed Diels-Alder reaction of 1-(2-furyl)-hex-1-en-5-yn-3-ol derivatives: A short and generalised route for the synthesis of hydroxyphenanthrene derivatives
Samanta, Khokan,Kar, Gandhi K.,Sarkar, Achintya K.
, p. 1376 - 1379 (2012/04/04)
Gold(III) catalysed intramolecular Diels-Alder reaction of various 1-(2-furyl)-hex-1-en-5-yn-3-ol derivatives has been studied to synthesise hydroxyphenanthrenes and other polynuclear aromatic hydroxyl compounds. The required precursors were synthesised by indium mediated propargylation of suitable β-furyl-α,β-unsaturated aldehydes.
A New and Concise Synthesis of 3-Hydroxybenzo[c]phenanthrene and 12-Hydroxybenzo[g]chrysene, Useful Intermediates for the Synthesis of Fjord-Region Diol Epoxides of Benzo[c]phenanthrene and Benzo[g]chrysene
Kumar, Subodh
, p. 8535 - 8539 (2007/10/03)
A new strategy which involves a palladium-catalyzed cross-coupling reaction has been developed for the rapid synthesis of 3-hydroxybenzo[c]phenanthrene (5) and 12-hydroxybenzo[g]chrysene (6). These phenolic compounds are the key intermediates for the synthesis of highly carcinogenic fjord-region diol epoxide metabolites 3 and 4 of benzo[c]phenanthrene (1) and benzo[g]chrysene (2). The cross-coupling reaction of 2-bromo-5-methoxybenzaldehyde (9) with naphthalene-1-boronic acid (7) and phenanthrene-9-boronic acid (8) produced 2-(1-naphthyl)-5-methoxybenzaldehyde (10) and 2-(9-phenanthryl)-5-methoxybenzaldehyde (11), respectively, in quantitative yields. After reaction of these aldehydes with trimethylsulfonium iodide under phase-transfer conditions or with the Wittig reagent obtained from (methoxymethyl)triphenylphosphonium bromide and phenyllithium to generate an oxiranyl or methoxyethene side chain, the acid-catalyzed cyclization with methanesulfonic acid (or boron trifluoride) produced 3-methoxybenzo[c]phenanthrene (16) and 12-methoxybenzo[g]chrysene (17) in 61-64percent yields. Finally, demethylation of these methoxy derivatives 16 and 17 with boron tribromide resulted in the formation of the hydroxy analogues 5 and 6, respectively. The availability of this short and high-yielding regiospecific method for the synthesis of phenols 5 and 6 should allow the preparative-scale synthesis of the fjord-region diol epoxides 3 and 4. These diol epoxides are required as starting compounds for the synthesis of site-specifically modified oligonucleotides which are critically needed to elucidate the mechanism of carcinogenesis at the molecular level.
An Efficient Synthesis of the Highly Tumorigenic anti-Diol Epoxide Derivative of Benzophenanthrene
Pataki, John,Raddo, Pasquale Di,Harvey, Ronald G.
, p. 840 - 844 (2007/10/02)
Synthesis of the potent tumorigen trans-3,4-dihydroxy-anti-1,2,3,4-tetrahydrobenzophenanthrene (1) in relatively few steps and superior overall yield is described.The method entails synthesis of the key intermediate 3-hydroxybenzophenanthrene (7b) v
