The efficient total synthesis of (-)-serotobenine (1) has been achieved by constructing an optically active dihydrobenzofuran ring via a rhodium carbenoid mediated intramolecular C-H insertion reaction, which was developed our group. Then the possibility racemization 1 investigated using synthetic 1.

Abstract Short total syntheses of natural glycosides (ellagitannins) were performed through sequential and regioselective functionalization the hydroxy groups unprotected glucose. The key reactions are β‐selective glycosidation a gallic acid derivative by using glucose as glycosyl donor catalyst‐controlled introduction galloyl group into inherently less reactive glucoside.

Claudin-2 is highly expressed in human lung adenocarcinoma tissues and may be a novel target for cancer chemotherapy because knockdown of claudin-2 decreases cell proliferation. We found that flavonoids including kaempferol, chrysin, luteolin concentration-dependently decrease expression A549 cells. up-regulated by mitogen-activated protein kinase (MEK)/ extracellular signal-regulated (ERK)/c-Fos phosphoinositide 3-kinase (PI3K)/Akt/nuclear factor-κB (NF-κB) pathways, but these activities...

Asymmetric synthesis of mechanically planar chiral rotaxanes and topologically catenanes has been a long-standing challenge in organic synthesis. Recently, an excellent strategy was developed based on diastereomeric with mechanical chirality followed by removal the auxiliary. On other hand, its enantioselective approach quite limited. Here, we report preparation kinetic resolution racemates via remote asymmetric acylation hydroxy group axis component, which provides unreacted enantiomer up...

Organocatalytic regioselective acylation of mono- and disaccaharides with various functionalized acid anhydrides has been developed. Acylation octyl beta-D-glucopyranoside derived from alpha-amino acids, cinnamic acid, gallic took place at C(4)-OH 67-94% regioselectivity in the presence catalyst 1. Regioselective disaccharides was also achieved 78-94% selectivity. Especially, a disaccharide seven free hydroxy groups (X = OH, R' H) underwent 78% Thus, functional group tolerance catalyzed by 1...

Acylation of lanatoside C in the presence organocatalyst 5 gave C(4'''')-O-acylate up to 90% regioselectivity (catalyst-controlled regioselectivity). Various functionalized acyl groups can be introduced at C(4'''')-OH by a mixed anhydride method or related organocatalyst. On other hand, DMAP-catalyzed acylation C(3'''')-O-acylate 97% (substrate-controlled Thus, diverse regioselective introduction among eight free hydroxy was achieved.

A palladium-mediated domino reaction was developed to conveniently synthesize phenanthridinone derivatives. Phosphine ligand 1 strongly promotes the process, which includes aryl−aryl coupling and C−N bond formations concomitant with a deamidation reaction. The versatility applicability broad range of substrates make this useful for development bioactive

Electronic tuning: Nitroxyl radical 1 is shown to be an efficient catalyst for the oxidation of secondary alcohols, and promotes through oxoammonium species which highly reactive because adjacent electron-withdrawing ester groups. Chemoselective benzylic alcohols in presence aliphatic observed proposed proceed by a rate-determining hydride transfer.

The first total syntheses of multifidosides A-C have been achieved. synthetic strategy is characterized by catalytic site-selective acylation unprotected glycoside precursors in the final stage synthesis. High functional-group tolerance acylation, promoted an organocatalyst, enabled conventionally difficult molecular transformation a predictable and reliable manner. An advantage this to avoid risks undesired side reactions during removal protecting groups at

Acylpyridinium ions have been known as catalytically active species in acylation reactions catalyzed by 4-dimethylaminopyridine and its analogues. carboxylates were found to be 800–1300 times more reactive than the corresponding acylpyridinium chlorides. A catalytic cycle was developed, which generated situ counteranion exchange from catalyst loading low 0.01 mol % turnover number of up 6700 achieved for site-selective a carbohydrate.

The stereoselective synthesis of the key intermediate for altemicidin has been accomplished. commenced with a bicyclo[3.3.0] framework, which was readily obtained via an intramolecular C−H insertion reaction. A Curtius rearrangement employed as step to stereoselectively construct β-hydroxyl α-disubstituted-α-amino acid structure. Synthesis vinylogous urea achieved using hydrolysis nitrile intermediate.

Abstract A perfectly regioselective and sequential method for the preparation of orthogonally protected glucopyranosides has been developed. An acyl group was introduced at C(4)‐OH by organocatalysis with >99 % regioselectivity. TBDPS, Boc, BOM groups were sequentially into 4‐ O ‐acyl‐glucopyranoside C(6)‐OH, C(2)‐OH, C(3)‐OH, respectively, ca. 100 regioselectivity in each step.

Abstract A nonenzymatic one-step procedure for the chemo- and regioselective acylation of carbohydrates has been developed. With 1 mol % an organocatalyst, octyl β-d-glucopyranoside took place preferentially on secondary hydroxy group at C(4) among four groups including primary C(6) in 99% selectivity 98% yield. This could be alternatively achieved by a conventional protection/deprotection via five steps 46% overall Thus, development present process is expected to contribute extremely...

Matters of length: Exclusive or predominant monoacylation 1,n-linear diols took place in the presence 1 when chain length linear was equal to shorter than five carbon atoms. The chemoselectivity acylation between 1,5-pentanediol (n=5) and 1,6-hexanediol (n=6) 5.2, that its monoacylate 113. Detailed facts importance specialist readers are published as ”Supporting Information”. Such documents peer-reviewed, but not copy-edited typeset. They made available submitted by authors. Please note:...

Abstract The aberrant expression of claudins (CLDNs), which are tight junctional proteins, is seen in various solid tumors, but the regulatory mechanisms and their pathophysiological role not well understood. Both CLDN1 CLDN11 were highly expressed human lung squamous cell carcinoma (SCC). Chrysin, found high concentration honey propolis, decreased RERF-LC-AI cells derived from SCC. phosphorylation level Akt was by chrysin, those ERK1/2 c-Jun not. LY-294002, an inhibitor phosphatidylinositol...

An SN2 mechanism was proposed for highly stereoselective glycosylation of benzoic acid with unprotected α-d-glucose under Mitsunobu conditions in dioxane, while an SN1 indicated nonstereoselective DMF. The SN2-type is generally applicable to various pyranoses as glycosyl donors combination a wide range acidic acceptors such carboxylic acids, phenols, and imides, retaining its high stereoselectivity (33 examples). Glycosylation α-d-mannose proceeded also manner directly afford usually less...

A one-pot, telescoped transformation of silyl ethers into cyanides that proceeds via silyl-ether oxidation mediated by nitroxyl-radical catalyst 1 and [bis(trifluoroacetoxy)iodo]benzene followed an imine formation-oxidation sequence using iodine aqueous ammonia is reported. This effective for the site-selective benzylic allylic in presence other ethers. Using O-protected oxime a catalytic amount triflic acid instead iodine/aqueous also cyanation.

Synthesis of numerous optically active rod-shaped oligo(2,3-dioxyfunctionalized)naphthalenes connected at their 1,4-positions was achieved using oxidative coupling under CuCl2/alpha-methylbenzylamine conditions by second-order asymmetric transformation. We believe this method is practical and should contribute to the field material science.

Novel optically active axially chiral amino acid and alcohols have been synthesized efficiently via lactam ring-opening, with the aid of an alcohol, amidoaza[5]helicene 5, which has readily prepared by additive-ligand-free Pd catalyzed domino coupling reaction in a single step. The stereostructures these molecules also clarified.

Highly chemo- and regioselective acylation of 2-aminopentane-1,5-diol derivatives has been achieved by organocatalysis. An acyl group can be chemoselectively introduced onto the sterically hindered secondary hydroxy in presence primary one virtue molecular recognition event catalyst.

We have developed 4-pyrrolidinopyridine catalysts for the geometry-selective (E-selective) acylation of tetrasubstituted α,α'-alkenediols. To elucidate major factors high geometry selectivity, experimental and computational studies were carried out. The control experiments with respect to substituent substrate indicated fundamental hydrogen bonding acidic NHNs Z-OH in substrate. Comparison between C2- C1-symmetric exhibited necessity C2-symmetric catalyst structure. computationally proposed...

The thianthrene scaffold has recently attracted significant attention in various coupling reactions. Although 5‐iminothianthrene and its derivatives are expected to function as electrophilic aminating reagents, their properties reactivity have not been fully investigated. In this work, it was found that reacted with electrophiles, such acid chlorides, protons, isothiocyanates give the corresponding adducts. addition, intramolecular chalcogen bonding (ChB) identified those adducts,...