The rearrangements of 1,5-hexadiene-3-oxide and 3-methyl-1,5-hexadiene-3-oxide have been studied in the gas phase, using both Fourier transform mass spectrometry (FTMS) and the flowing afterglow (FA) technique. Gas-phase studies of ionic rearrangements can be limited by analysis techniques such as collision-induced dissociation, which have the potential of driving the rearrangement prior to fra...

The first total synthesis of (+/-)-actinophyllic acid (1) is reported. Key steps of this synthesis include an intramolecular oxidative coupling of ketone and malonic ester enolates and an aza-Cope-Mannich rearrangement that assembled the core structure of the natural product's unique ring system. The synthesis was accomplished from di-tert-butyl malonate in 8% overall yield by a concise sequenc...

Treatment of (E)-1-(methoxymethylene)-1,2,3,4-tetrahydronaphthalene with styryl diazoacetates in the presence of catalytic amounts of the dirhodium complex Rh2(S-DOSP)4 provides a highly enantioenriched hexacyclic product with 10 new stereogenic centers. The transformation proceeds by a cascade sequence starting with a double cyclopropanation of a benzene ring, followed by a Cope rearrangement ...

A novel NHC-catalyzed three-component domino strategy to access high functionalized cis-ε-ketoesters with excellent yields (up to 98%) and high stereoselectivities (up to 20:1) is documented. The title domino reactions are atom economical and work on a broad range of substrates. The relative stereochemistry could be explained by a cascade crossed-benzoin/oxy-Cope rearrangement/esterification pr...

The hemisynthesis of the naturally occurring bioactive flavonoid glycoside icariin (1) has been accomplished in eleven steps with 7% overall yield from kaempferol. The 4'-OH methylation of kaempferol, the 8-prenylation of 3-O-methoxymethyl-4'-O-methyl-5-O-prenyl-7-O-benzylkaempferol (8) via para-Claisen-Cope rearrangement catalyzed by Eu(fod)3 in the presence of NaHCO3, and the glycosylation of...

The development of new catalytic asymmetric reactions can lead to exciting new strategies for organic synthesis. This article describes the synthetic utility of the combined C-H activation/Cope rearrangement, achieved by dirhodium tetraprolinate-catalyzed reaction of vinyldiazoacetates with compounds containing allylic C-H bonds. The transformation is highly diastereoselective and enantioselect...

The application of 2-arylcyclopropylmethanols as substitutes to homoallyl aryl alcohols and their reactions with aliphatic aldehydes in the presence of SnCl4 in CH2Cl2 leads to an efficient Prins cyclization to generate cis-2,6-disubstituted tetrahydropyrans in high yields. The reaction is free from 2-oxonia-Cope rearrangement. This protocol was used to synthesize (±)-centrolobine in an overall...

The year 2022 has been one of hybrid events all over the world, as we emerge from effects and aftereffects COVID-19. With repercussions still lingering, there are many aspects that need to be addressed before announcing any event. We geared up attend IEEE Antennas Propagation Society (AP-S) International Symposium on Propagation/U.S. National Committee–International Union Radio Science Meeting ...

Cationic tri-tert-butylphosphinegold(I) serves as a catalyst in the sila-Cope rearrangement of acetylenic allylsilanes. When phenol is employed as a nucleophile, the reaction allows for the stereoselective synthesis of vinylsilanes. Alternatively, use of methanol as a nucleophile leads to cyclic vinylsilanes, which can be viewed as latent vinylsilanes that are revealed on treatment with a mild ...

α-Aminations of ketone-derived nitrones have been developed via [3,3]-rearrangement of the intermediates generated upon condensation with imidoyl chlorides. Careful reagent selection provides synthetically attractive amino protecting groups. The enediamide or α'-carbamoyl enamide products can be hydrolyzed to the desired carbonyl, or exposed to electrophiles for further α-functionalization.