1,1-Divinyl-2-phenylcyclopropanes are entry points to a rich area of rearrangement chemistry. With N,N-diallyl amide substrates, tandem radical cyclizations can be initiated at room temperature. Warming provides products of pure thermal rearrangements with acids, ester, and amides. These isomerizations give vinylcyclopentenes resulting from divinylcyclopropane rearrangements and more deeply rea...

A domino sequence has been developed between vinyldiazoacetates and racemic allyl alcohols, involving five distinct steps. The sequence generates highly functionalized cyclopentanes with four new stereogenic centers as single diastereomers in 64-92% ee. The first step is a rhodium-catalyzed oxygen ylide formation, which is then followed by a [2,3]-sigmatropic rearrangement, an oxy-Cope rearrang...

The potential energy surface of the rearrangement of 3-vinylmethylenecyclobutane to 4-methylenecyclohexene has been studied computationally using density functional theory (B3LYP) and complete active space ab initio methods (CASSCF and CASPT2). The parent reaction is nonconcerted and occurs through several parallel diradical pathways. Transition structures and diradical intermediates are highly...

A four-step stereocontrolled synthesis of polyfunctionalized cis-decalins is described, involving oxidation of 2-methoxyphenol, intermolecular Diels-Alder reaction, olefination, and Cope rearrangement. Application of this efficient strategy to the total syntheses of (()-eremopetasidione, (()-3â-angeloyloxyfuranoeremophilane, and (()-3â-methacryloyloxyfuranoeremophilane was accomplished from cre...

The first total synthesis of the tetracyclic alkaloid (-)-acutumine is described. Key reactions include an asymmetric ketone allylation mediated by Nakamura's chiral allylzinc reagent, an anionic oxy-Cope rearrangement, and the Lewis acid-promoted cyclization of an amine onto an alpha,beta-unsaturated dimethyl ketal.

A catalytic, enantioselective γ-alkylation of α,β-unsaturated malonates and ketoesters is reported. This strategy entails a highly regio- and enantioselective iridium-catalyzed α-alkylation of an extended enolate, and a subsequent translocation of chirality to the γ-position via a Cope rearrangement.

In reactions with weak dienophiles, cyclooctatetraene (COT) often yields 2:1 adducts possessing the fluxional bicyclo[5.1.0]octadiene moiety. They undergo fast, nearly degenerate Cope rearrangement with an activation barrier similar to that of the parent dihydrobullvalene. Irradiation to excite the carbonyl moiety induces an intramolecular Paterno-Buchi cyclization yielding endo-oxetanes and si...

A set of mild processes for the conversion of vinyl cyclopropyl diazo ketones to highly functionalized cycloheptadienones and vinyl cyclopentenones by use of a target-inspired tandem Wolff/Cope rearrangement sequence is described. A divergent reaction course of the vinyl cyclopropyl diazo ketone substrates under sono- or photochemical activation provides good to excellent yields (55-98%) of the...

The 3-aza-Cope rearrangements of 3-azoniahexa-1,5-diene (1), 3-azoniahex-1-ene-5-yne (3), and 3-azahex-1-ene-5-yne (5) were investigated up to the coupled-cluster level, CCSD(T), by using a valence triple-zeta basis set. Activation barriers and geometrical parameters of the transition states are provided. Conformational studies were performed for all reactants and products of the reactions. Sol...

Pinostrobin (5-hydroxy-7-methoxyflavanone) obtained in relatively large amounts from fingerroot (Boesenbergia pandurata) was converted to its C-6 and C-8 prenylated derivatives. The Mitsunobu reaction, europium(III)-catalyzed Claisen-Cope rearrangement, and Claisen reaction coupled with cross-metathesis were used as the key steps. Using a sealed-vessel microwave reactor, the Mitsunobu and Clais...