Mechanistic Studies on Garratt–Braverman Cyclization: The Diradical–Cycloaddition Puzzle
作者:Joyee Das、Subhendu Sekhar Bag、Amit Basak
DOI:10.1021/acs.joc.6b00490
日期:2016.6.3
In this work, we present the results of extensive multiprong studies involving the fate of deuterium-labeled substrates, EPR, trapping experiments, and LA-LDI mass spectrometry to sort out the controversies relating to the mechanism of Garratt–Braverman cyclization in two systems, namely bis-propargyl sulfones and ethers. The results are in conformity with a diradical mechamism for the sulfone, while
Easily prepared and air-stable methylidynetricobaltnonacarbonyl could be used as a catalyst for the intramolecular [2 + 2 + 1]-cocyclization of diynes and carbon monoxide producing cyclopentadienones.