Microwave-assisted cycloaddition of diisopropyl diazomethylphosphonate to electron-deficient alkenes: synthesis of multifunctionalized phosphonopyrazolynes and phosphonopyrazoles

作者：Marinozzi Maura^*; Tondi Silvia; Marcelli Gloria; Giorgi Gianluca

来源：Tetrahedron, 2014, 70(50): 9485-9491.

DOI：10.1016/j.tet.2014.10.069

• Phosphorous-containing diazo compounds
• Phosphonopyrazolines
• Phosphonopyrazoles
• 1,3-Dipolar cycloaddition
• Privileged structures

An efficient method for the synthesis of functionalized phosphonopyrazolines has been developed. The procedure involved the microwave-assisted cycloaddition of diisopropyl diazomethylphosphonate to dipolarophiles, such as ex,alpha,beta-unsaturated-nitriles and -esters, performed in neat conditions. By oxidative aromatization the phosphonopyrazolines, thus obtained, were converted into the corresponding phosphonopyazoles Alternatively, phosphonopyazoles could be obtained by a one-pot, two step procedure directly from dipolarophiles, thus avoiding the isolation of the intermediate pyrazolines. Full spectroscopic characterization of the compounds has been also reported.

• 出版日期2014-12-16