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Selective one-pot synthesis of substituted pyrrole-3-phosphonates from alpha-cyanomethyl-beta-ketoesters

2007-05-07
Demir, Ayhan Sıtkı
Tural, Servet
A one-step synthesis of 5-alkoxypyrrole-3-phosphonates is presented starting from suitable alpha-cyanomethyl-beta-ketophosphonates. The key step in the synthesis involves a one-pot addition and heteroannulation sequence. The zinc perchlorate-catalyzed addition of alcohols to the nitrile carbon of alpha-cyanomethyl- beta-ketophosphonates followed by annulation furnished 5-alkoxypyrrole-3-phosphonates. The addition-annulation process is carried out in the presence of water and 4,5-dihydro-5-oxo-1H-pyrrole-3-phosphonates (pyrrolinones) are obtained in good yields.