Kounosuke Oisaki 교수

A procedure for making covalently linked organometallic complexes within the pores of metal-organic frameworks (MOFs) has been described. An N-heterocyclic carbene precursor containing link L0 was prepared and then constructed into a MOF-5-type structure (IRMOF-76). Attempts to produce covalently bound organometallic complexes in IRMOF-76 were unsuccessful. An alternative way of linking the first metalated link, L1, into the desired metalated MOF structure, IRMOF-77, was successful. IRMOF-76 and

The development of a general, mild, and chemoselective catalytic aerobic oxidation of amines to imines is described. The combination of a less sterically demanding and electron-deficient new N-oxyl radical (ketoABNO: 5) and copper(I) salt is key for the high catalytic activity and allows for the use of molecular oxygen as the stoichiometric oxidant producing H2O as the sole side-product. The novel method is extendable to a direct α-derivatization of secondary amines via sequential aerobic oxidat

An enantioselective aldol reaction between ketones and ketene silyl acetals is described using CuF-chiral phosphine as a catalyst. The key for high enantioselectivity was the development of a novel ligand derived from Taniaphos combined with the unique accelerative effect of PhBF3K. These conditions are applicable to various substrates such as aromatic, aliphatic, and heteroaromatic ketones. In the case of substituted nucleophiles, the reaction proceeds well. The diastereoselectivity is independ

A new method for the catalytic aldol reaction to ketones, using CuF.3PPh3.2EtOH complex as the catalyst and (EtO)3SiF as the additive, is described. The reaction can be applied to a wide range of ketones and trimethylsilyl enolates. On the basis of mechanistic studies, a working hypothesis for the catalytic cycle is proposed, in which the dynamic ligand exchange mediated by copper silicates produces the active copper enolate. Moreover, the present reaction can be extended to the catalytic enanti

A catalytic amount of a sterically and electronically tuned diarylsulfonamide promoted allylic and benzylic C-H arylations in cooperation with a visible light photoredox catalyst. This is the first example of the catalytic use of a sulfonamidyl radical to promote the hydrogen atom transfer process.

A general catalytic asymmetric alkylative aldol reaction is described as a new entry to the catalytic asymmetric multicomponent reaction (CAMCR). Highly functionalized delta-lactones were produced in the presence of a catalytic amount of the Cu(OAc)2-DIFLUORPHOS complex through three-component assembly of dialkylzincs, allenic esters, and unactivated ketones. This CAMCR constructs two C-C bonds and one tetrasubstituted chiral center simultaneously. Conjugate addition of alkylcopper species to an

Inspired by the reaction mechanism of photo-induced DNA cleavage in nature, a C(sp³ )-H cyanation reaction promoted by visible-light photoredox/phosphate hybrid catalysis was developed. Phosphate radicals, generated by one-electron photooxidation of phosphate salt, functioned as a hydrogen-atom-transfer catalyst to produce nucleophilic carbon radicals from C(sp³ )-H bonds with a high bond-dissociation energy. The resulting carbon radicals were trapped by a cyano radical sou

The site-specific cleavage of peptide bonds is an important chemical modification of biologically relevant macromolecules. The reaction is not only used for routine structural determination of peptides, but is also a potential artificial modulator of protein function. Realizing the substrate scope beyond the conventional chemical or enzymatic cleavage of peptide bonds is, however, a formidable challenge. Here we report a serine-selective peptide-cleavage protocol that proceeds at room temperatur

Abstract The development of catalyst‐controlled site‐selective C( sp 3 )−H functionalization is a current major challenge in organic synthesis. This paper describes DFT‐guided identification of pentavalent silicate species as a novel bond‐weakening catalyst for the α‐C−H bonds of alcohols together with a photoredox catalyst and a hydrogen atom transfer catalyst. Specifically, Martin's spirosilane accelerated α‐C−H alkylation of alcohols. magnified image

Chemically reactive directing groups (directing activators) represent a promising strategy for mild and regioselective C(sp³)-H functionalization. The use of a radical <i>N</i>-oxyl directing activator promoted the aerobic oxygenation of benzylic, propargylic, tertiary, and unactivated acyclic methylene C(sp³)-H bonds in aliphatic alcohols with γ- (or δ-) selectivity under mild conditions (room temperature to 50 °C). The reaction was unaffected by the presence of various ox

Post-translational modifications (PTMs) of proteins are a biological mechanism for reversibly controlling protein function. Synthetic protein modifications (SPMs) at specific canonical amino acids can mimic PTMs. However, reversible SPMs at hydrophobic amino acid residues in proteins are especially limited. Here, we report a tyrosine (Tyr)-selective SPM utilizing persistent iminoxyl radicals, which are readily generated from sterically hindered oximes via single-electron oxidation. The reactivit

We describe the first example of manganese(III)-catalyzed aerobic dehydrogenative cyclization producing ring-fused indole skeletons. This catalytic system converts from two C-H bonds of indole and malonate to a C-C bond and produces water as the sole side product. This operationally easy method was extended to an intermolecular cross-dehydrogenative coupling of indole and α-substituted malonate with complete C2-selectivity.