Search

Stereoselective alkyne semihydrogenations are attractive approaches to alkenes, which are key building blocks for synthesis. With regards to the most atom‐economic reducing agent dihydrogen (H2), only few catalysts for the challenging E‐selective alkyne semihydrogenation have been disclosed, each with a unique substrate scope profile. Here, we show that a commercially available nickel catalyst facilitates the E‐selective alkyne semihydrogenation of a wide variety of substituted internal alkynes. This results in a simple and broadly applicable overall protocol to stereoselectively access E‐alkenes employing H2, which could serve as a general method for synthesis., Keep E simple: A simple and commercially available nickel catalyst for E‐selective alkyne semihydrogenation is presented. The protocol is practical and encompasses a wide variety of internal alkynes.

The copper-catalyzed multicomponent reaction of 2-iodobenzamides, NaN3 and terminal alkynes for the synthesis of 2-(1,2,3,-triazolyl)benzamide derivatives was achieved in a one-step process and short period of time under mild reaction condition. The transformations consisted of C(aryl)-N bond formation and azide-alkyne cycloadditon. The absence of an external base was found to be crucial in determining the preferred reaction pathway.

Quinoline derivatives were obtained from enaminones and 2-bromo- or 2-iodobenzaldehydes via copper-catalyzed domino reactions consisting of the aldol reaction, C(aryl)-N bond formation and elimination. The electronic effect of aldehydes played a major role in the reaction outcome. Two simple protocols are disclosed to achieve various quinolines from both cyclic and acyclic enaminones in good yields. With the less-reactive acyclic enaminones, diethyl-2-(2-bromobenzylidene)malonate was shown to be more compatible than the benzaldehydes.

A simple and commercially available nickel catalyst for E-selective alkyne semihydrogenation is presented. The protocol is practical and encompasses a wide variety of internal alkynes, with aryl and alkyl substituents tolerated alike.

Zearalenone is a β-resorcylic acid macrolide with various biological activities. Herein we report the synthesis and cytotoxic activities of 34 zearalenone analogues against human oral epidermoid carcinoma (KB) and human breast adenocarcinoma (MCF-7) cells as well as noncancerous Vero cells. Some zearalenone analogues showed moderately enhanced cytotoxic activities against the two cancer cell lines. We have discovered the potential lead compounds with diminished or no cytotoxicity to Vero cells. Preliminary structure-activity relationship studies revealed that the double bond at the 1' and 2' positions of zearalenone core was crucial for cytotoxic activities on both cell lines. In addition, for zearalenol analogues, the unprotected hydroxyl group at C-2 and an alkoxy substituent at C-4 played key roles on cytotoxic effects of both cell lines.

sec-Benzyl azides were efficiently prepared by bismuth(III)-catalyzed direct azidation of sec-benzyl alcohols. The reaction was applied to a variety of substrates to provide the desired products in up to 99% yield within a short reaction time.

This direct azidation process provides secondary and tertiary benzyl azides in high yields and short reaction times, whereas primary benzyl alcohol (Ig) fails to react.