Morifumi Fujita

Asymmetric synthesis of 4,8-dihydroxyisochroman-1-one polyketide metabolites using chiral hypervalent iodine(III).

Stereoselective oxylactonization of ortho-alkenylbenzoate with chiral hypervalent iodine is applied to the asymmetric synthesis of 4-oxyisochroman-1-one polyketide metabolites including 4-hydroxymellein (1), a derivative of fusarentin 2, monocerin (3), and an epimer of monocerin epi-3.

A series of two oxidation reactions of ortho-alkenylbenzamide with hypervalent iodine(III): a concise entry into (3R,4R)-4-hydroxymellein and (3R,4R)-4-hydroxy-6-methoxymellein.

A sequence of oxidation reactions of alkenamides with hypervalent iodine is described. Oxidation of ortho-alkenylbenzamide substrates selectively gave isochroman-1-imine products. The products underwent further oxidation in the presence of a Pd salt catalyst leading to regioselective C-H acetoxylation at the 8-position. A series of oxidations was applied to the crucial steps of asymmetric synthesis of 4-hydroxymellein derivatives.

Field and Electroantennogram Responses of the Pine Sawfly, Diprion nipponica, to Chiral Synthetic Pheromone Candidates

(1S, 2R, 6RS)-1,2,6-Trimethyldecyl propionate, a lower homolog of the sex pheromone of known sawflies, strongly attracted Diprion nipponica, a popular species in Japan.

Total synthesis of (12R)- and (12S)-12-hydroxymonocerins: stereoselective oxylactonization using a chiral hypervalent iodine(III) species

The first total syntheses of (12R)- and (12S)-12-hydroxymonocerins are described. The oxolane-fused isochroman-1-one framework is stereoselectively constructed via a double oxy-cyclization using a lactate-based chiral hypervalent iodine reagent. A catalytic variant of the double oxy-cyclization is also demonstrated using a chiral iodoarene as the precatalyst and m-CPBA as the co-oxidant.

Thermal decomposition of alkenyliodonium tetrafluoroborates: a novel route to fluoroalkenes

Alkenyl(phenyl)iodonium tetrafluoroborates dissolved in chloroform, or in the solid state, decompose thermally at 60°C to yield fluoroalkenes and iodobenzene as major products via an SN1- or SN2-type reaction within the ion pair of the substrates.

Metal-Free Enantioselective Oxidative Arylation of Alkenes: Hypervalent-Iodine-Promoted Oxidative C−C Bond Formation

The enantioselective oxyarylation of (E)-6-aryl-1-silyloxylhex-3-ene was achieved using a lactate-based chiral hypervalent iodine(III) reagent in the presence of boron trifluoride diethyl etherate. The silyl ether promotes the oxidative cyclization, and enhances the enantioselectivity. In addition, the corresponding aminoarylation was achieved.

Importance of steric hindrance in linear coordination of Lewis acids with α-enones

The complexation of α-enones [(E)-MeC(H)C(H)COR] with SnCl4 and TiCl4 has been studied with NMR spectroscopy as well as semiempirical and ab initio SCF-MO methods, which indicate a preference for linear coordination of Lewis acids with α-enones due to the steric effect of R group (R = But, Ph, 2,4,6-Me3C6H2, 4-MeOC6H4) in the s-cis conformation.

Stereoselective Formation of Substituted 1,3-Dioxolanes through a Three-Component Assembly during the Oxidation of Alkenes with Hypervalent Iodine(III)

Stereoselective formation of substituted 1,3-dioxolanes was achieved through an assembly of three components: alkene, carboxylic acid and silyl enol ether. The reaction proceeded via stereospecific generation of a 1,3-dioxolan-2-yl cation intermediate during oxidation of alkene substrates with hypervalent iodine. The stereoselective trapping of the cation intermediate with silyl enol ether completed the formation of the dioxolane product.

Dispiroketals in synthesis. Part 25.1 Further reactions of dispiroketal protected glycolate to afford optically active 1,2,3,4-tetraols

Glycolic acid can be converted to optically active 1,2,3,4-tetraols using a dispiroketal unit as a protecting group and chiral auxiliary. Aldol reactions of dispiroketal protected glycolate with aldehydes afford one diastereoisomer preferentially with two newly formed stereogenic centres. To extend the polyol chain, the carbonyl group of the aldol product is converted to a vinyl ether by the Tebbe reagent after protection of the free alcohol. A subsequent hydroboration–oxidation protocol affords the dispiroketal protected tetraol. The final deprotection of the tetraol occurs selectively without epimerisation or migration of the silyloxy protecting groups.

Enantioselective dioxytosylation of styrenes using lactate-based chiral hypervalent iodine(III)

A series of optically active hypervalent iodine(III) reagents prepared from the corresponding (R)-2-(2-iodophenoxy)propanoate derivative was employed for the asymmetric dioxytosylation of styrene and its derivatives. The electrophilic addition of the hypervalent iodine(III) compound toward styrene proceeded with high enantioface selectivity to give 1-aryl-1,2-di(tosyloxy)ethane with an enantiomeric excess of 70–96% of the (S)-isomer.