An Efficient Stereoselective Synthesis of 4,5-trans-1,5-cis-3-Oxabicyclo[3.1.0]hexan-2-ones via the Iodolactonization of Alkylidenecyclopropyl Esters

A modular approach to highly functionalized 3-sulfonylfurans via conjugate addition of 3-cyclopropylideneprop-2-en-1-ones with sodium sulfinates and sequential 5-endo-trig iodocyclization

Conjugate addition of 3-cyclopropylideneprop-2-en-1-ones with sodium sulfinates and sequential 5-endo-trig iodocyclization to afford valuable 3-sulfonylfurans.

Gold-catalyzed intermolecular synthesis of alkylidenecyclopropanes through catalytic allene activation

A stereoselective gold(I)-catalyzed intermolecular cyclopropanation of allenamides with stabilized sulfonium ylides is reported. This transformation enables the direct synthesis of diacceptor alkylidenecyclopropanes and proceeds under very mild conditions through allene activation.

Diversity-oriented synthesis as a tool for identifying new modulators of mitosis

The synthesis of diverse three-dimensional libraries has become of paramount importance for obtaining better leads for drug discovery. Such libraries are predicted to fare better than traditional compound collections in phenotypic screens and against difficult targets. Herein we report the diversity-oriented synthesis of a compound library using rhodium carbenoid chemistry to access structurally diverse three-dimensional molecules and show that they access biologically relevant areas of chemical space using cheminformatic analysis. High-content screening of this library for antimitotic activity followed by chemical modification identified 'Dosabulin', which causes mitotic arrest and cancer cell death by apoptosis. Its mechanism of action is determined to be microtubule depolymerization, and the compound is shown to not significantly affect vinblastine binding to tubulin; however, experiments suggest binding to a site vicinal or allosteric to Colchicine. This work validates the combination of diversity-oriented synthesis and phenotypic screening as a strategy for the discovery of biologically relevant chemical entities.

Ozonation of methylenecyclopropanes

Ozonation of methylenecyclopropanes bearinggem-disubstituted electron-withdrawing groups (EWG) gave ring-opened oxidative products in moderate to good yields.

Stereoselective Rh2(S-IBAZ)4-catalyzed cyclopropanation of alkenes, alkynes, and allenes: asymmetric synthesis of diacceptor cyclopropylphosphonates and alkylidenecyclopropanes

A mild and highly stereoselective rhodium(II)-catalyzed cyclopropanation of alkenes, alkynes, and allenes with diacceptor diazo compounds is reported. Using the phosphonate moiety as an efficient trans-directing group, the first catalytic asymmetric route to diacceptor cycloprop(en)ylphosphonates was developed by employing an α-cyano diazophosphonate and Rh(2)(S-IBAZ)(4) as chiral catalyst. The isosteric character of phosphonic and carboxylic acid derivatives allowed the alternative use of an α-cyano diazo ester in the process, leading to α-cyano cycloprop(en)ylcarboxylates in high yields and stereoselectivities. Taking advantage of the particular reactivity of the cyanocarbene intermediates involved in this system, the scope of compatible substrates could be extended to substituted allenes, leading to the development of the first catalytic enantioselective method for the synthesis of diacceptor alkylidenecyclopropanes.

Heterocycles based on the chemistry of alkylidenecyclopropanes and (aza)-cyclopropenes

Alkylidenecyclopropyl, cyclopropenyl, or azacyclocyclopropenyl ketones or carboxylates have been demonstrated to be versatile starting materials for the synthesis of oxygen- and/or nitrogen-containing heterocycles. The reactivities and regioselectivities may be nicely controlled by subtle choice of the catalysts and reaction condition parameters.

Intermolecular Tandem Addition−Cyclization of Bromoallenes: A Facile Synthesis of Methylenecyclopropyl Carboxylates and Polysubstituted Furans

The base-mediated reactions of 1,3-dicarbonyl compounds with bromoallenes used as an allyl dication equivalent were explored. The corresponding dimethyl methylenecyclopropane-1,1-dicarboxylates and 2,3,4-trisubstituted furans were efficiently synthesized. [reaction: see text]