New efficient and flexible synthesis of polysubstituted pyrroles
作者:Dieter Enders、Sin-Ho Man、Ralf Maaβen
DOI:10.1016/0040-4039(95)01717-v
日期:1995.10
The Lewis acid mediated reaction of readily available 2-acetoxypropanal-N,N-dimethylhydrazone 1 with various open chain and cyclic silyl enol ethers 2 leads directly or via 4-oxoaldehyde-N,N-dimethylhydrazones 3 to N-(dimethylamino)-pyrroles 4. The subsequent reductive N-N bond cleavage provides an efficient and flexible method for the preparation of alkyl-aryl-di- and trisubstituted pyrroles 5.
New Efficient, Flexible and Regioselective Synthesis of 2,4-Di- and 2,3,4-Trialkylated an Arylated 1H-Pyrroles
作者:Dieter Enders、Ralf Maaßen、Sin-Ho Han
DOI:10.1002/jlac.199619961011
日期:1996.10
Starting from easily available 2-acetoxy aldehyde dimethylhydrazones rac-2, we prepared various alkyl- and aryl-substituted 1H-pyrroles 6 in good overall yield. The titariummediated a2-umpolung reaction of rac-2 with different acyclic and cyclic silyl enol ethers 3 leads directly or via 4-oxo hydrazones rac,anti-4 to 1-(dimethylamino)-1H-pyrroles 5. A novel method for the reductive removal of the dimethylamino