Intramolecular Hetero Diels−Alder (Povarov) Approach to the Synthesis of the Alkaloids Luotonin A and Camptothecin
摘要:
Pyrrolo[3,4-b]quinolines can be formed through the coupling of anilines with N-propargylic substituted heterocyclic aldehydes in the presence of mild Lewis acid catalysts (Ln(OTf)(3)). The coupling proceeds through sequential imine formation and a formal intramolecular aza-Diels-Alder (Povarov) reaction. This approach was applied in a total synthesis of luotonin A and a formal synthesis of camptothecin.
One-Pot, Two-Step Cascade Synthesis of Quinazolinotriazolobenzodiazepines
摘要:
An operationally simple, one-pot, two-step cascade method has been developed to afford quinazolino[1,2,3]triazolo[1,4]benzodiazepines. This unique, atom-economical transformation engages five reactive centers (amide, aniline, carbonyl, azide, and alkyne) and employs environmentally benign iodine as a catalyst. The method proceeds via sequential quinazolinone-forming condensation and intramolecular azide-alkyne 1,3-dipolar cycloaddition reactions. Substrate scope, multicomponent examples, and mechanistic insights are discussed.
Gold(I)‐Catalyzed Selective Cyclization and 1,2‐Shift to Prepare Pseudorutaecarpine Derivatives
作者:Wang Wang、Nan‐Ying Chen、Pei‐Sen Zou、Li Pang、Dong‐Liang Mo、Cheng‐Xue Pan、Gui‐Fa Su
DOI:10.1002/adsc.202101054
日期:2022.2.15
pseudorutaecarpine derivatives were prepared in good to excellent yields through a gold(I)-catalyzed selective cyclization and 1,2-shift of N-alkynyl quinazolinone-tethered indoles. Mechanistic study revealed that spiroindolenines generated in situ by cyclization at the the indole C3 position underwent an alkenyl 1,2-shift to generate pseudorutaecarpine. The reaction proceeds under mild reaction conditions
furnacalis (Guenée) and inhibition of this enzyme has been considered a promising strategy for the development of eco-friendly pesticides. In this article, based on the structure of the catalytic domains of OfHex1, a series of novel glycosyl triazoles were designed and synthesized via Cu-catalyzed azide-alkyne [3+2] cycloaddition reaction. To investigate the potency and selectivity of these glycosyl triazoles
henylazo)benzoic acid (HAZA) scaffold, the orthogonally protected difunctional azo–arene cleavablelinker 26 was designed and synthesized. Selective linker deprotection and derivatization was performed by introducing an alkyne reactive group and a biotin affinity tag. This optimized azo–arene cleavablelinker led to a total cleavage in less than 10 s with only 1 mM dithionite. Similar results were