Direct cyanation of heteroaromatic compounds mediated by hypervalent iodine(III) reagents: In situ generation of PhI(III)-CN species and their cyano transfer.

Hypervalent iodine(III) reagents mediate the direct cyanating reaction of a wide range of electron-rich heteroaromatic compounds such as pyrroles 1, thiophenes 3, and indoles 5 under mild conditions (ambient temperature), without the need for any prefunctionalization. Commercially available trimethylsilylcyanide is usable as a stable and effective cyanide source, and the reaction proceeds in a homogeneous system. The N-substituent of pyrroles is crucial to avoid the undesired oxidative bipyrrole coupling process, and thus a cyano group was introduced selectively at the 2-position of N-tosylpyrroles 1 in good yields using the combination of phenyliodine bis(trifluoroacetate) (PIFA), TMSCN, and BF3.

The first total synthesis of discorhabdin A.

The first stereoselective total synthesis of a potent antitumor alkaloid, discorhabdin A (1), which is a unique sulfur-containing pyrroloiminoquinone alkaloid, is described. The key step in the stereocontrolled total synthesis of 1 involves both a diastereoselective oxidative spirocyclization using a hypervalent iodine(III) reagent and an efficient construction of the labile and highly strained N,S-acetal skeleton. These methodologies provide a breakthrough in the total syntheses of these promising new antitumor agents, discorhabdins and their analogues, which should serve as valuable probes for structure-activity studies.

The synthesis of head-to-tail (H-T) dimers of 3-substituted thiophenes by the hypervalent iodine(III)-induced oxidative biaryl coupling reaction.

The head-to-tail (H-T) dimers could be obtained selectively by the oxidative coupling reaction of 3-substituted thiophenes using a combination of hypervalent iodine(III) reagents and trimethylsilyl trifluoromethanesulfonate.

A unique site-selective reaction of ketones with new recyclable hypervalent iodine(III) reagents based on a tetraphenylmethane structure.

We have synthesized new recyclable reagents having a tetraphenylmethane backbone and used them in the site-selective alpha-tosyloxylation of ketones.

Novel and direct oxidative cyanation reactions of heteroaromatic compounds mediated by a hypervalent iodine(III) reagent.

The hypervalent iodine(III) reagent phenyliodine bis(trifluoroacetate) (PIFA) mediates the selective cyanation reactions of a wide range of electron-rich heteroaromatic compounds such as pyrroles, thiophenes, and indoles under mild conditions. These reactions proceed via a cation radical intermediate, and the key for the successful transformation presumably depends on the oxidation-reduction potential of the substrates used. The synthetic utility has been demonstrated through the conversion of these biologically important pyrroles 2f and 2g.

A novel and concise synthesis of spirodienone alkaloids using hypervalent iodine(III) reagents.

Intramolecular oxidative coupling reaction of N-protected benzyltetrahydroisoquinoline derivatives using hypervalent iodine(III) reagents was investigated. The use of remarkable combination of phenyliodine bis (trifluoroacetate) (PIFA) and heteropoly acid (HPA) in wet acetonitrile smoothly afforded morphinandienone alkaloids, while neospirinedienone alkaloids were obtained in high yield under anhydrous conditions.

The efficient synthesis of morphinandienone alkaloids by using a combination of hypervalent iodine(III) reagent and heteropoly acid.

The non-phenolic coupling reaction of benzyltetrahydroisoquinolines (laudanosine derivatives) by using a hypervalent iodine(III) reagent is described. In general, chemical oxidation of laudanosine gives glaucine. In contrast to general chemical oxidizing reagent systems, the novel use of reagent combination of phenyliodine bis(trifluoroacetate) (PIFA), and heteropoly acid (HPA) afforded morphinandienone alkaloids in excellent yields.

A novel and direct synthesis of alkylated 2,2'-bithiophene derivatives using a combination of hypervalent iodine(III) reagent and BF3.Et2O.

A novel nonmetallic oxidative coupling of alkylthiophene derivatives leading to the corresponding 2,2'-bithiophene derivatives using a combination of a hypervalent iodine(III) reagent, phenyliodine bis(trifluoroacetate) (PIFA), and BF3.Et2O was developed.

A novel and useful oxidative intramolecular coupling reaction of phenol ether derivatives on treatment with a combination of hypervalent iodine(III) reagent and heteropoly acid.

The oxidative intramolecular coupling reaction of phenol ether derivatives (nonphenolic derivatives) on treatment with a novel combination of a hypervalent iodine(III) reagent, phenyliodine bis(trifluoroacetate) (PIFA), and heteropoly acid (HPA) was studied. Biaryl compounds were obtained in excellent yields on treatment of highly substituted phenol ethers. On the other hand, spirodienones were specifically formed when one of the preferred arylic coupling sites was substituted with a methoxy group in the para position.

A novel and efficient oxidative biaryl coupling reaction of phenol ether derivatives using a combination of hypervalent iodine(III) reagent and heteropoly acid.

A novel and efficient oxidative biaryl coupling reaction of phenol ether derivatives using a combination of hypervalent iodine(III) reagent, phenyliodine(III) bis(trifluoroacetate) (PIFA), and heteropoly acid has been developed.

Hypervalent Iodine(V)-Induced Asymmetric Oxidation of Sulfides to Sulfoxides Mediated by Reversed Micelles: Novel Nonmetallic Catalytic System.

Although several types of chiral hypervalent iodine reagents have been used for asymmetric induction, all of them have needed more than a stoichiometric amount of chiral reagents and have shown low enantioselectivities. The described new catalytic asymmetric oxidation using a hypervalent iodine(V) reagent, iodoxybenzene (PhIO(2)), in a cationic reversed micellar system provides the first example of a catalytic asymmetric oxidation of sulfides to sulfoxides in high chemical yield with moderate to good enantioselectivity without the use of any transition-metal catalysts. The solubilization and activation of PhIO(2) by adding catalytic amounts of both cetyltrimethylammonium bromide (CTAB) and a chiral tartaric acid derivative were found to be indispensable for the enhancement of chemical and optical yields.