Isocyanide-based multicomponent reactions (IMCR) are by far the most versatile reactions that can construct relatively complex molecules by one-pot synthesis. More importantly, the development of post IMCR modifications significantly improves the scaffold's diversity. Here, we describe the use of N-Boc protected hydrazine together with α-amino acid derived isocyanides in the Ugi tetrazole react...

E- and Z-9-Methyldeca-3,8-dien-1-ols undergo smooth cyclization with aldehydes in the presence of 20 mol% AgSbF6 under extremely mild conditions to generate the corresponding oxa-bicycles in good yields with excellent selectivity. In fact, E-olefin affords the trans-product exclusively, whereas the Z-olefin gives the cis-product predominantly. In the case of E- or Z-8-methylnona-3,8-dien-1-ol, ...

A practical catalytic approach to the synthesis of 4-substituted 1,2,3,4-tetrahydro-beta-carbolines (THBCs, 1) and 1,2,3,9-tetrahydropyrano[3,4-b]indoles (2) via InBr3-catalyzed intramolecular Friedel-Crafts (F-C) cyclization is described. The use of cross-metathesis reaction represents a direct route to the cyclization precursors and the use of InBr3 (5 mol%) allowed polycyclic indole compound...

In this manuscript, we describe the synthesis of the carbohydrazide 2. Acid-catalyzed condensation with several carbonyl compounds to afford the corresponding carbohydrazide derivatives 3-12. Their acetylation afforded the corresponding acetyl derivatives 13-22. Oxidative cyclization of O-acetyl derivatives 19-22 afforded the corresponding 1,3,4-oxadiazole derivatives 23-2...

Cell-free extracts prepared by sonication of Streptomyces clavuligerus cyclized 6-(L-aaminoadipyl)-L-cysteinyl-D-valine (ACV) into a penicillin-type antibiotic. The antibacterial spectrum of this antibiotic suggested it was a mixture of isopenicillin N and penicillin N indicating that both cyclization and racemase activities were present. Cyclization activity was optimal in extracts prepared fr...

Highly enantioselective catalytic intramolecular ortho-alkylation of aromatic imines containing alkenyl groups tethered at the meta position relative to the imine directing group has been achieved using [RhCl(coe)2]2 and chiral phosphoramidite ligands. Cyclization of substrates containing 1,1- and 1,2-disubstituted as well as trisubstituted alkenes were achieved with enantioselectivities >90% e...

A short and efficient synthesis of cinnoline-fused cyclic enediyne is reported. Richter cyclization of o-(1,3-butadiynyl)phenyltriazene produced 3-alkynyl-4-bromocinnoline. The Sonogashira coupling of the latter with 5-hexyn-1-ol was employed for the introduction of a second acetylenic moiety. The crucial cyclization step was achieved under Nozaki-Hiyama-Kishi conditions. Cinnoline-fused 10-mem...

We have applied T4 ligase-mediated DNA cyclization kinetics to protein-induced bending in DNA. The presence and direction of a static bend can be inferred from J factors for cyclization of 150- to 160-base-pair minicircles, which include a catabolite activator protein binding site phased against a sequence-directed bend. We demonstrate a quasi-thermodynamic linkage between cyclization and prote...

Explaining the oxidation–cyclization mechanism of heterocycles containing Te−O bonds. The structures halogenated Te-containing have been elucidated, and computational methods showed them to be prepared in a two-step oxidation–cyclization. three compounds shown represent both structural diversity biological application these hypervalent as leishmanicides. More information can found Full Paper by...

Aromatic polyketides make up a large class of natural products with diverse bioactivity. During biosynthesis, linear poly-β-ketone intermediates are regiospecifically cyclized, yielding molecules with defined cyclization patterns that are crucial for polyketide bioactivity. The aromatase/cyclases (ARO/CYCs) are responsible for regiospecific cyclization of bacterial polyketides. The two most com...