Donor–Acceptor Cyclopropanes as 1,2-Dipoles in GaCl<sub>3</sub>-Mediated [4 + 2]-Annulation with Alkenes: Easy Access to the Tetralin Skeleton
作者:Roman A. Novikov、Anna V. Tarasova、Victor A. Korolev、Evgeny V. Shulishov、Vladimir P. Timofeev、Yury V. Tomilov
DOI:10.1021/acs.joc.5b01179
日期:2015.8.21
A new process for (4 + 2)-annulation of donor–acceptorcyclopropanes (DACs) with unsaturated compounds in the presence of anhydrous GaCl3 has been developed. In this process, DACs act as sources of formal1,2- and 1,4-dipoles to give polysubstituted tetralins in high yields and with high regio- and diastereoselectivity. Alkenes with both aryl and alkyl substituents at the double bond undergo this reaction
novel method for synthesizing seven‐membered ring carbocycles via a palladium‐catalyzed intramolecular allylic alkylation–isomerization–Cope rearrangement cascade. DFT calculation for the seven‐membered ring formation step suggested that, in addition to the reaction cascade including the conventional Cope rearrangement, there is another possible pathway via retro‐cyclopropanation.
Lewis Acid-Catalyzed Isomerization of 2-Arylcyclopropane-1,1-dicarboxylates: A New Efficient Route to 2-Styrylmalonates
作者:Alexey O. Chagarovskiy、Olga A. Ivanova、Eduard R. Rakhmankulov、Ekaterina M. Budynina、Igor V. Trushkov、Mikhail Ya. Melnikov
DOI:10.1002/adsc.201000636
日期:2010.12.17
A facile efficient approach to the 2-styrylmalonates via the Lewis acid-catalyzedisomerization of 2-arylcyclopropane-1,1-dicarboxylates has been developed. The efficiency of this method was demonstrated for a representative series of such cyclopropanes. The isomerization proceeds chemo-, regio- and stereoselectively to afford E-styrylmalonates in good yields.
Styrylmalonates as an Alternative to Donor–Acceptor Cyclopropanes in the Reactions with Aldehydes: A Route to 5,6-Dihydropyran-2-ones
作者:Denis D. Borisov、Roman A. Novikov、Anna S. Eltysheva、Yaroslav V. Tkachev、Yury V. Tomilov
DOI:10.1021/acs.orglett.7b01556
日期:2017.7.21
cyclopropanes (DAC) has been suggested. It involves the use of isomeric styrylmalonates as alternative sources of reactive intermediates. The efficiency of the approach has been demonstrated in reactions with aromatic aldehydes. As a result, a new process for construction of the 5,6-dihydropyran-2-one skeleton has been developed. It efficiently occurs with high diastereoselectivity in the presence of BF3·Et2O;
New dimerization and cascade oligomerization reactions of dimethyl 2-phenylcyclopropan-1,1-dicarboxylate catalyzed by Lewis acids
作者:Roman A. Novikov、Victor A. Korolev、Vladimir P. Timofeev、Yury V. Tomilov
DOI:10.1016/j.tetlet.2011.07.001
日期:2011.9
New routes to transform donor–acceptor cyclopropanes in the presence of Lewisacids have been found. The reaction of dimethyl 2-phenylcyclopropan-1,1-dicarboxylate, a typical representative of this class of compounds, with an equimolar amount of anhydrous GaCl3 gives, depending on the reaction time, (2-phenylethylidene)malonate or styrylmalonate after hydrolysis, whereas in the presence of 15–20 mol %