A divergent synthetic strategy to 1,6-dihydropyridazines and pyridazines through Cu(II)-catalyzed controllable aerobic 6-endo-trig cyclization was developed. The selectivity can be rationally tuned via the judicious choice of reaction solvent. It was found that the 1,6-dihydropyridazines were obtained in moderate to high yields with CH3CN as the reaction solvent, whereas employment of AcOH directly
C<sub>sp<sup>3</sup></sub>–C<sub>sp<sup>3</sup></sub> Bond Cleavage in the Palladium-Catalyzed Aminohydroxylation of Allylic Hydrazones Using Atmospheric Oxygen as the Sole Oxidant
作者:Yu-Chen Chen、Ming-Kui Zhu、Teck-Peng Loh
DOI:10.1021/acs.orglett.5b01127
日期:2015.6.5
A C–C bond cleavage was observed in the palladium-catalyzed aminohydroxylation of allylic hydrazones, using atmospheric oxygen as the soleoxidant. This reaction could also proceed in a one-pot manner, starting from keto-alkene compounds and phenylhydrazine.
Simple, commercially available iodine was successfully employed as a highly efficient and chemoselective catalyst for the oxidative annulation of β,γ-unsaturatedhydrazones to produce 1,6-dihydropyridazines under mild conditions for the first time. Interestingly, when active β,γ-unsaturatedhydrazone compounds containing electron-donating groups, such as furyl, thienyl, and cycloalkyl, were used, pyrroles