Novel formal [2+3] cycloaddition between substituted phenols and furan

Total synthesis of (±)-decursivine via BINOL-phosphoric acid catalyzed tandem oxidative cyclization

The synthesis of tetracyclic indole alkaloid (±)-decursivine was accomplished using BINOL-phosphoric acid catalyzed tandem oxidative cyclization as a key step with (bis(trifluoroacetoxy)iodo)benzene (PIFA) as an oxidizing agent. This represents one of the shortest and highest yielding routes for the synthesis of (±)-decursivine from readily available starting materials.

One-step formation of dihydrofuranoindoline cores promoted by a hypervalent iodine reagent

Treatment of aniline derivatives in the presence of a hypervalent iodine reagent and furan produces dihydrofuranoindoline cores in one step.

Advances in Synthetic Applications of Hypervalent Iodine Compounds

The preparation, structure, and chemistry of hypervalent iodine compounds are reviewed with emphasis on their synthetic application. Compounds of iodine possess reactivity similar to that of transition metals, but have the advantage of environmental sustainability and efficient utilization of natural resources. These compounds are widely used in organic synthesis as selective oxidants and environmentally friendly reagents. Synthetic uses of hypervalent iodine reagents in halogenation reactions, various oxidations, rearrangements, aminations, C-C bond-forming reactions, and transition metal-catalyzed reactions are summarized and discussed. Recent discovery of hypervalent catalytic systems and recyclable reagents, and the development of new enantioselective reactions using chiral hypervalent iodine compounds represent a particularly important achievement in the field of hypervalent iodine chemistry. One of the goals of this Review is to attract the attention of the scientific community as to the benefits of using hypervalent iodine compounds as an environmentally sustainable alternative to heavy metals.

A facile access to cis-dihydrofurobenzofuran from 2-(2,5-dihydro-furan-2-yl)-phenol

An access to cis-dihydrofurobenzofuran from the Pd-catalyzed intramolecular oxidation of 2-(2,5-dihydro-furan-2-yl)-phenol with moderate to good yields is reported.

Oxidative Heterocycle Formation Using Hypervalent Iodine(III) Reagents

Hypervalent iodine(III) reagents have been widely exploited in a diverse array of synthetic transformations. This chapter focuses on the general application of hypervalent iodine(III) reagents in the de novo synthesis and in the late stage functionalization of heterocyclic compounds.

Photocatalytic synthesis of dihydrobenzofurans by oxidative [3+2] cycloaddition of phenols

We report a protocol for oxidative [3+2] cycloadditions of phenols and alkenes applicable to the modular synthesis of a large family of dihydrobenzofuran natural products. Visible-light-activated transition metal photocatalysis enables the use of ammonium persulfate as an easily handled, benign terminal oxidant. The broad range of organic substrates that are readily oxidized by photoredox catalysis suggests that this strategy may be applicable to a variety of useful oxidative transformations.

Total synthesis and repudiation of the helianane family

Total syntheses of two structures purported as (+)-heliananes were completed in six pots. Spectral comparisons, between the synthetic and natural compounds, revealed a misassignment of the eight-membered ring in the heliananes. The key step in the syntheses of the proposed structures and the confirmation of their actual structures was a diastereoselective inverse-demand Diels-Alder reaction between an optically active enol ether and an ortho-quinone methide species, which was generated in situ at low temperature by the sequential addition of methylmagnesium bromide and di-tert-butyl dicarbonate to a salicylaldehyde.

Total synthesis of platensimycin and related natural products

Platensimycin is the flagship member of a new and growing class of antibiotics with promising antibacterial properties against drug-resistant bacteria. The total syntheses of platensimycin and its congeners, platensimycins B(1) and B(3), platensic acid, methyl platensinoate, platensimide A, homoplatensimide A, and homoplatensimide A methyl ester, are described. The convergent strategy developed toward these target molecules involved construction of their cage-like core followed by attachment of the various side chains through amide bond formation. In addition to a racemic synthesis, two asymmetric routes to the core structure are described: one exploiting a rhodium-catalyzed asymmetric cycloisomerization, and another employing a hypervalent iodine-mediated de-aromatizing cyclization of an enantiopure substrate. The final two bonds of the core structure were forged through a samarium diiodide-mediated ketyl radical cyclization and an acid-catalyzed etherification. The rhodium-catalyzed asymmetric reaction involving a terminal acetylene was developed as a general method for the asymmetric cycloisomerization of terminal enynes.

Expeditious total syntheses of natural allenic products via aromatic ring umpolung

Concise diastereoselective syntheses of the marine (+/-)-panacene and terrestrial (+/-)-desbromopanacene have been achieved in a few steps based on a concept of "aromatic ring umpolung". The synthetic avenue to the (+/-)-panacene involved a novel oxymercuration strategy to produce the correct configuration of the bromoallene moiety.

Improved procedure for the bimolecular oxidative amidation of phenols

Trifluoroacetic acid (TFA) is an effective promoter of the bimolecular Ritter-like oxidative amidation of 4-substituted phenols induced by PhI(OAc) 2 in MeCN. This suppresses the need for fluoroalcohol cosolvents, increases the yields, and facilitates isolation/purification procedures.