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This report describes the one‐pot direct N‐acylation of indazole with carboxylic acids using our previously developed 4‐(N,N‐dimethylamino)pyridine N‐oxide (DMAPO)/di‐tert‐butyl dicarbonate (Boc2O) system. This simple system provides N1‐acyl indazoles in high yield with high N1 selectivities and does not require the use of activated derivatives of carboxylic acids or high temperatures. This new method exhibits a wide substrate scope (>40 examples). In addition, a new synthesis of N1‐functionalized alkyl indazoles utilizing N1‐acyl indazoles as starting materials was achieved. This stepwise protocol is useful for the selective synthesis of structurally diverse N1‐functionalized alkyl indazoles, which are difficult to synthesize by other methods such as the Mitsunobu reaction and classical SN2 alkylation of indazole. [ABSTRACT FROM AUTHOR]

This report describes a general method for the one‐pot direct N‐acylation of N‐heterocycles using our previously developed 4‐(N,N‐dimethylamino)pyridine N‐oxide (DMAPO)/di‐tert‐butyl dicarbonate (Boc2O) system. This system enables one‐pot N‐acylation reactions to provide bulky N‐acyl heterocycles starting from a wide variety of less nucleophilic N‐heterocycles and sterically hindered α‐fully substituted carboxylic acids in high yields. Moreover, this one‐pot method does not involve pre‐activation of substrates. The protocol has been successfully extended to one‐pot N‐acylation of 7‐azaindoles. [ABSTRACT FROM AUTHOR]

In contrast to the considerable progress in the development of methodologies for amide bond formation in amines, the development of direct N‐acylation of less nucleophilic N‐heterocycles and amides with carboxylic acids is still challenging. In this report, we describe the direct N‐acylation of less nucleophilic heterocycles and amides with carboxylic acids promoted by the 4‐(N,N‐dimethylamino)pyridine N‐oxide (DMAPO)/di‐tert‐butyl dicarbonate (Boc2O) system. The new one‐pot method, which does not involve pre‐activation of substrates, enables the direct N‐acylation of a wide variety of nitrogen nucleophiles such as indole, carbazole, pyrrole, pyrazole, lactam, oxazolidinone, and anilide with carboxylic acids in high yield. The new method also exhibits excellent functional group tolerance and broad substrate scope. As the present method is practical, operationally simple, and scalable, it should find wide applications in both academic and industrial laboratories. [ABSTRACT FROM AUTHOR]

The density, viscosity, self-diffusion coefficient and other such properties of various liquid samples of oleic acid are measured to evaluate and understand the effects of cholesterol and other additives on its viscosity. The analysis show that cholesterol highly increases the viscosity of the oleic acid, as they have a tendency to form a complex between them and hence helps in proper study of the inter- and intramelocular movements o the acid in the liquid state.

Total syntheses ofleuconodine B, melodinine E, and leuconoxinewere accomplished via a divergent route. The [5.5.6.6]diazafenestraneskeleton was constructed from an indole-3-acetamide derivative viaDMDO oxidation to hydroxylindolenine, TMSOTf/2,6-lutidinemediated cyclic aminal formation, and diastereoseletive ring-closingmetathesis of a triene derivative. [ABSTRACT FROM AUTHOR]

L-tert-Leucine was found to be an effective organocatalyst for the asymmetric aldol reaction of chloroacetone. The stereo-selective synthesis of vic-halohydrins was accomplished with excellent regioselectivity (>99%) to generate α-chloro-β-hydroxy ketones with high syn selectivity (syn/anti = 16:1) and enantioselectivity (up to 95% ee). [ABSTRACT FROM AUTHOR]

Our efforts toward the synthesis of the marine natural product portimine are described. The key to the synthesis of the skeleton is a stereoretentive copper-catalyzed C( sp 3 )-C( sp 2 ) Stille-type cross-coupling that enables the convergent assembly of functionalized fragments. The core skeleton of portimine was constructed via ring-closing metathesis and transannular acetal formation.

The total synthesis of the resorcylic acid lactones (-)-zearalenone and (-)-zearalanone is described. Our synthetic strategy relies on Ni-, Zr-, and Cr-mediated intramolecular reductive ketone coupling to create 14-membered macrolactones. Notably, the use of CrCl 2 in addition to Ni/Zr-mediated reductive ketone coupling conditions was key for the success of the macrocyclization.

The total synthesis of marine macrolide glycoside (-)-irijimaside A is described. Key to the synthesis is the convergent fragment assembly enabled by nickel/zirconocene-mediated one-pot reductive ketone coupling. At the last stage of the synthesis, Stille coupling and glycosylation led to the first total synthesis of (-)-irijimaside A.