Friedel-Crafts-Type Reactions with Electrochemically Generated Electrophiles from Donor-Acceptor Cyclopropanes and -Butanes.

We describe a general electrochemical method to functionalize donor-acceptor (D-A) cyclopropanes and -butanes with arenes utilizing Friedel-Crafts-type reactivity. The catalyst-free strategy relies on the direct anodic oxidation of the strained carbocycles, which leads after C(sp)-C(sp) cleavage to radical cations that act as electrophiles for the arylation reaction. Broad reaction scopes in regard to cyclopropanes, cyclobutanes, and aromatic reaction partners are presented.

-Selective, Enantiospecific Addition of Donor-Acceptor Cyclopropanes to Activated Alkenes: An Iodination/Michael-Cyclization Cascade.

We present a versatile method for the enantiospecific, -diastereoselective intermolecular and intramolecular cycloaddition of donor-acceptor cyclopropanes to electron-poor alkenes with cyclic acceptor groups to afford highly substituted spirocyclopentanes in good to excellent yields. The reaction can be applied to biologically interesting scaffolds, including barbiturates and isoxazolones. Mechanistic investigations were undertaken to explain the unusual diastereoselectivity and enantiospecificity; these suggest an iodination/Michael-cyclization cascade.

Substituted Benzothietes: Synthesis and a Quantum Chemical Investigation of Their Cycloreversion Properties.

A flexible synthesis for highly substituted benzothietes that does not require flash-vacuum pyrolysis was developed. This allows for the use of a number of functional groups and nonvaporizable molecules. Highly stabilized derivatives were isolated.