Synthesis of Spiro Barbiturates and Meldrum’s Acid Derivatives via a [2+2+2] Cyclotrimerization
作者:Sambasivarao Kotha、Gaddamedi Sreevani
DOI:10.1055/s-0037-1610238
日期:2018.12
and Meldrum’sacid derivatives containing a spiro linkage. Furthermore, we have extended this methodology to synthesize linearly fused Meldrum’sacid derivatives via Diels–Alder reaction using rongalite chemistry. Intermolecular [2+2+2] cycloaddition of propargyl halides with 1,6-diynes was accomplished with a catalytic amount of Mo(CO)6 to generate benzyl halo barbiturates and Meldrum’sacid derivatives
Atom-Economic Route to Cyanoarenes and 2,2′-Dicyanobiarenes via Iron-Catalyzed Chemoselective [2 + 2 + 2] Cycloaddition Reactions of Diynes and Tetraynes with Alkynylnitriles
An efficient protocol for the synthesis of cyanoarenes has been developed via an iron-catalyzed chemoselective [2 + 2 + 2] cycloadditionreaction of diynes with alkynylnitriles under mild reaction conditions with good to excellent yields. The reaction is catalyzed by the combination of FeCl2·4H2O as a metal source, 2-(2,6-diisopropylphenyl)iminomethylpyridine (dipimp) as a ligand, and Zn as a reducing
Additive-Controlled Switchable Selectivity from Cyanobenzenes to 2-Alkynylpyridines: Ruthenium(II)-Catalyzed [2+2+2] Cycloadditions of Diynes and Alkynylnitriles
作者:Divya Bhatt、Neha Patel、Hrishikesh Chowdhury、Prasad V. Bharatam、Avijit Goswami
DOI:10.1002/adsc.201800228
日期:2018.5.2
developed by the reaction of 1,6‐diynes with alkynylnitriles using chloro(pentamethylcyclopentadienyl) (cyclooctadiyne)ruthenium(II) as catalyst in dimethoxyethane (DME). The course of the reaction can be drastically altered simply by adding a catalytic amount of AgOTf as an additive resulting in a comprehensive shift in product formation from cyanoarenes to 2‐alkynylpyridines. Theoreticalstudies clearly indicate
A Combined Transition-Metal-Catalyzed and Photopromoted Process: Synthesis of 2,3-Fused 4-Phenylnaphthalen-1-yl Carboxylates from 1,7-Diaryl-1,6-diynes
2,3‐Fused 4‐phenylnaphthalen‐1‐yl carboxylates were synthesized in a step‐ and atom‐economical manner using a ruthenium‐catalyzed hydrocarboxylative cyclization of 1,7‐diaryl‐1,6‐diynes and subsequent oxidative photocyclization. The scope of this novel two‐step process was demonstrated by the construction of diverse structures from substrates with various tethers and terminal aryl groups. Late‐stage
An efficient method to access 2‐triazolyl thio‐/selenopyridines with good to excellent yields by ruthenium(II)‐catalyzedone‐pot [3+2]/[2+2+2] cycloaddition reactions of azides, 1‐alkynyl thio‐/selenocyanates and 1,6‐diynes is reported. This atom‐economical catalytic strategy offers a mild and practical approach to access a variety of such cycloadducts with good to excellect regioselectivities. The