Oxidative Cyclization Reaction of 2-Aryl-Substituted Cinnamates To Form Phenanthrene Carboxylates by Using MoCl<sub>5</sub>
作者:Kathrin Wehming、Moritz Schubert、Gregor Schnakenburg、Siegfried R. Waldvogel
DOI:10.1002/chem.201403442
日期:2014.9.22
The oxidative cyclization reaction of 2‐aryl cinnamates and derivatives thereof can be easily performed with MoCl5 as the oxidant. This powerful reagent allows oxidative coupling reactions for which other reagents fail. The best results are obtained when the 2‐phenyl substituent of the cinnamate is equipped with two methoxy groups. Even iodo moieties in the bay region of phenanthrene are tolerated
Molybdenum Pentachloride Mediated Synthesis of Spirocyclic Compounds by Intramolecular Oxidative Coupling
作者:Moritz Schubert、Kathrin Wehming、Anton Kehl、Martin Nieger、Gregor Schnakenburg、Roland Fröhlich、Dieter Schollmeyer、Siegfried R. Waldvogel
DOI:10.1002/ejoc.201501384
日期:2016.1
The oxidative treatment of (m)ethyl 2-aryl cinnamates equipped with methoxy groups in position 4 of the phenyl moiety promote the formation of cyclohexadienone substructures. This dealkylative oxidative C–C coupling gives access to spirocycliccompounds and avoids the construction of the corresponding phenanthrenes. Furthermore, the transformation can be expanded to other spirocyclic systems.
The copper-mediated reaction of phosphinyl-stabilized carbanions 2a-c with aryl halides 1a-i in DMF or HMPA produced (arylmethyl)phosphonates 3-11 in good yields. Similar treatment of N-(2-iodophenyl)- and N-(2-iodophenyl)-N-methyl-alpha-(diethoxyphosphinyl)acetamides (12 and 14) led to 2-[(diethoxyphosphinyl)methyl]benzoxazole (13) and 1-methyl-3-(diethoxyphosphinyl)oxindole (15) in 71 and 85% yields, respectively. 4-(Ethoxycarbonyl)-3,4-dihydroisoquinoline N-oxide (33) was synthesized by the reaction of ethyl alpha-(o-formylphenyl)acrylate (31), derived from 6 and paraformaldehyde,with hydroxylamine. The cycloaddition of 33 to olefins such as dimethyl maleate, methyl acrylate, and styrene was studied.
Route to α-Aryl Phosphonoacetates: Useful Synthetic Precursors in the Horner–Wadsworth–Emmons Olefination
作者:Kelsey F. VanGelder、Melinda Wang、Marisa C. Kozlowski
DOI:10.1021/acs.joc.5b01887
日期:2015.10.16
A versatile and general catalytic strategy has been developed for the alpha-arylation of phosphonoacetates utilizing parallel microscale experimentation. These a-substituted phosphonoacetates are widely useful, notably as substrates in the Horner-Wadsworth-Emmons-type olefinations. However, the current routes to these products involve harsh conditions, limiting the variety of functionality. The reported method can be used with a variety of aryl chlorides and aryl bromides, including several heterocyclic examples.
Minami Toru, Isonaka Takeshi, Okada Yoshiharu, Ichikawa Junji, J. Org. Chem, 58 (1993) N 25, S 7009-7015