Beilstein J. Org. Chem.2011,7, 601–605, doi:10.3762/bjoc.7.70
cyclobutene; allene; allenyloxindole; chirallanthanideshiftreagent; chiral transfer; Introduction
The [2 + 2] cycloaddition reaction of allenes and alkynes provides rapid entry into synthetically challenging alkylidene cyclobutene ring systems. We, along with others, have demonstrated the intramolecular
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Graphical Abstract
Scheme 1:
Conversion of propargyl acetate 1 to spirooxindole 2 containing the core framework of welwitindolin...