Lewis Acid-Mediated Transformations oftrans-2-Aroyl-3-aryl- cyclopropane-1,1-dicarboxylates into 2-Pyrones and 1-Indanones
摘要:
Abstracttrans‐2‐Aroyl‐3‐arylcyclopropane‐1,1‐dicarboxylates upon treatment with aluminium(III) chloride (AlCl3) underwent ring‐opening, fragmentation, recombination and lactonization to give highly substituted 2‐pyrones. Alternatively, when treated with titanium(IV) chloride (TiCl4), the cyclopropane diesters underwent a Nazarov cyclization to afford 1‐indanones with high diastereoselectivity.magnified image
The [3 + 2] annulations of γ-butyrolactone fused donor–acceptor (D–A) cyclopropanes with aromatic isothiocyanates and dialkyl carbodiimides promoted by FeCl3 is reported. A series of bicyclic/polycyclic γ-butyrolactone fused thioimidates and γ-butyrolactone fused amidines containing four contiguous stereogenic centers were obtained in excellent yields as single stereoisomers.
cis-2,3-Disubstituted cyclopropane 1,1-diesters were found to be much more reactive than their corresponding trans-isomers in the AlCl3-promoted [3 + 2]-annulations with isothiocyanates. The reaction with the cis-cyclopropanes proceeded to completion within minutes, providing a variety of densely substituted diastereomerically pure 2-iminodihydrothiophenes in moderate to excellent yields.
Solvent-Controlled Oxidative Cyclization for Divergent Synthesis of Highly Functionalized Oxetanes and Cyclopropanes
作者:Yang Ye、Chen Zheng、Renhua Fan
DOI:10.1021/ol9012102
日期:2009.7.16
An efficient solvent-controlled oxidative cyclization of Michael adducts of malonates with chalcones with the combination of iodosobenzene and tetrabutylammonium iodide is reported. Highly functionalized oxetanes and cyclopropanes were divergently synthesized in moderate to excellent yields with high diastereoselectivity.
Scandium(III) Triflate-Catalyzed Reaction of Aroyl-Substituted Donor–Acceptor Cyclopropanes with 1-Naphthylamines: Access to Dibenzo[<i>c</i>,<i>h</i>]acridines
作者:Murugesan Thangamani、Kannupal Srinivasan
DOI:10.1021/acs.joc.0c02105
日期:2021.1.1
The reaction of aroyl-substituted donor–acceptor (D–A) cyclopropanes with two equivalents of 1-naphthylamines in the presence of a catalytic amount of scandium(III) triflate provides access to dibenzo[c,h]acridines. The key steps of the transformation are the formation of nucleophilic ring-opening products from the D–A cyclopropanes and 1-naphthylamines and their subsequent fragmentation and cyclization
SnCl<sub>4</sub>-Promoted [3+2] Annulation of γ-Butyrolactone-Fused Donor–Acceptor Cyclopropanes with Nitriles: Access to γ-Butyrolactone-Fused 1-Pyrrolines
作者:V. John Tamilarasan、Kannupal Srinivasan
DOI:10.1021/acs.joc.9b01155
日期:2019.7.5
γ-butyrolactone-fused donor–acceptor cyclopropanes with nitriles has been explored for the access of γ-butyrolactone-fused 1-pyrrolines. The annulation was promoted by tin(IV) chloride, and the products were obtained as single diastereomers in moderate to good yields. The products were synthetically important, and a couple of them were subjected to tandem reductivering opening/cyclization to give the respective