Deconjugative conversion of alpha-alkynyl esters to alpha,alpha-disubstituted beta-alkynyl esters.
We report the development of a method for the conversion of a variety of conjugated alpha-alkynyl esters to alpha,alpha-disubstituted beta-alkynylesters through the use of strong amide bases. Studies indicate that the second equivalent of base leads to the dianion intermediate. Optimal conditions included the use of 2 equiv of lithium diisopropylamide in THF with HMPA as the cosolvent followed by trapping with a variety of carbon electrophiles. Trapping with bis-electrophiles leads to spiro cycloalkane products.
Lepore
Salvatore D
SD
Department of Chemistry, Florida Atlantic University, Boca Raton, FL 33431-0991, USA. slepore@fau.edu
He
Yuanjun
Y
D000480:Alkynes / Q000138:chemical synthesis / Q000737:chemistry*; D000577:Amides / Q000737:chemistry; D002384:Catalysis; D004952:Esters / Q000138:chemical synthesis / Q000737:chemistry*; D007202:Indicators and Reagents; D015394:Molecular Structure; D013237:Stereoisomerism
D000480:Alkynes; D000577:Amides; D004952:Esters; D007202:Indicators and Reagents