Efficient Stereoselective Syntheses of Cyclic Amino Acids via Michael-Induced Ring-Closing Reactions
作者:Matthias Pohlman、Uli Kazmaier
DOI:10.1021/ol034777j
日期:2003.7.1
[reaction: see text] Zn-chelated glycine ester enolates are highly efficient nucleophiles for the synthesis of trans-methoxycarbonylcyclopropyl- and cyclobutylglycines by domino sequences of Michael additions and subsequent ring closures. They react to give the anti isomers with high yields and excellent diastereoselectivities.
Allylic Alkylation versus Michael Induced Ring Closure: Chelated Enolates as Versatile Nucleophiles
作者:Matthias Pohlman、Uli Kazmaier、Thomas Lindner
DOI:10.1021/jo049036q
日期:2004.10.1
Allyliccarbonates 8 bearing an electron-withdrawing ester functionality can act as substrates for palladium-catalyzedallylic alkylations or as Michael acceptors with the option to undergo subsequent ring closure. Chelated amino acid ester enolates 1‘ are versatile nucleophiles for both reactions giving high yields and selectivites.