Enantiospecific Sn(II)- and Sn(IV)-catalyzed cycloadditions of aldehydes and donor-acceptor cyclopropanes
Patrick D Pohlhaus1, Jeffrey S Johnson
1Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, USA.
Abstract:
A cycloaddition strategy for the synthesis of highly enantioenriched 2,5-cis-disubstituted tetrahydrofurans has been developed. In the presence of catalytic Sn(OTf)2 or SnCl4, a range of aldehydes will undergo formal [3 + 2] cycloadditions with a scalemic donor-acceptor cyclopropane to form optically active heterocycles. Mechanistic studies support an unusual SN2 attack by the aldehyde on the activated cyclopropane. Through this mechanism, stereochemical information contained in the cyclopropane is effectively transferred to the tetrahydrofuran products.
More Related Videos
Related Concept Videos
Metal-Ligand Bonds
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
SN2 Reaction: Mechanism
The presence of the more electronegative halogen in the substrate creates a polarized carbon-halide bond. The halide pulls the electron cloud generating an electrophilic center at the carbon atom. Thus, the carbon atom carries a partial positive charge while the halide has a...
SN2 Reaction: Stereochemistry
If the substrate is an achiral molecule at the α-carbon, the inversion of configuration is not observed.
SN1 Reaction: Mechanism
Firstly, the haloalkane ionizes to generate a carbocation intermediate and a halide ion. This heterolytic cleavage is highly endothermic with large activation energy. The ionization of the substrate, facilitated by a polar...
Metabolism of Chemolithotrophs
Sulfur Assimilation

![The Synthesis of [Sn10(Si(SiMe3)3)4]2- Using a Metastable Sn(I) Halide Solution Synthesized via a Co-condensation Technique](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F54498.jpg&w=3840&q=50)
