Scope and Mechanism for Lewis Acid-Catalyzed Cycloadditions of Aldehydes and Donor−Acceptor Cyclopropanes: Evidence for a Stereospecific Intimate Ion Pair Pathway
作者:Patrick D. Pohlhaus、Shanina D. Sanders、Andrew T. Parsons、Wei Li、Jeffrey S. Johnson
DOI:10.1021/ja8015928
日期:2008.7.1
In this work, the one-step diastereoselective synthesis of cis-2,5-disubstituted tetrahydrofuransviaLewis acid catalyzed [3 + 2] cycloadditions of donor-acceptor (D-A) cyclopropanes and aldehydes is described. The scope and limitations with respect to both reaction partners are provided. A detailed examination of the mechanism has been performed, including stereochemical analysis and electronic profiling
GaCl<sub>3</sub>
-Mediated Reactions of Donor-Acceptor Cyclopropanes with Aromatic Aldehydes
作者:Denis D. Borisov、Roman A. Novikov、Yury V. Tomilov
DOI:10.1002/anie.201603927
日期:2016.9.26
A new strategy for cascade assembly of substituted indenes and polycyclic lactones based on reactions of donor–acceptor cyclopropanes and styrylmalonates with aromaticaldehydes in the presence of GaCl3 has been developed. The use of GaCl3 makes it possible to principally change the direction of the reaction known in this series of substrates and to perform the process in a multicomponent version. Generation
Highly diastereoselective formation of 3,7-dioxabicyclo[3.3.0]octan-2-ones in reaction of 2-arylcyclopropanedicarboxylates with aromatic aldehydes using 1,2-zwitterionic reactivity type
作者:Denis D. Borisov、Roman A. Novikov、Yury V. Tomilov
DOI:10.1016/j.tetlet.2017.08.025
日期:2017.9
A newreaction of 2-arylcyclopropane-1,1-dicarboxylates (ACDC) with aromaticaldehydes that occurs via generation of a 1,2-zwitterionic intermediate in the presence of GaCl3 has been developed. This process results in the 3,7-dioxabicyclo[3.3.0]octane frame by addition of two aldehyde molecules to an ACDC molecule. The reaction is a complex anionic-cationic cascade process involving the formation of
Highly Diastereoselective Synthesis of Tetrahydrofurans via Lewis Acid-Catalyzed Cyclopropane/Aldehyde Cycloadditions
作者:Patrick D. Pohlhaus、Jeffrey S. Johnson
DOI:10.1021/jo048230+
日期:2005.2.1
A one-step procedure for the preparation of 2,5-disubstituted tetrahydrofurans from donor-acceptor cyclopropanes and aldehydes has been developed. In the presence of a catalytic amount of Sn(OTf)(2), cyclopropanes bearing an aryl or conjugated donor substituent vicinal to a malonyl diester group undergo cycloadditions with diverse conjugated aldehydes furnishing tetrahydrofurans with high cis diastereoselectivity. This method is useful for the preparation of regiodefined tetrahydrofurans.