Transmetalation of Z-Telluroenynes: Stereoselective Synthesis of Z-Enynols and Their Application in Palladium-Catalyzed Cyclization
摘要:
The synthesis of various Z-enynols via reaction of vinyllithium intermediate with aldehydes and ketones is described. The subsequent cyclization of a wide variety of Z-enynols afforded substituted furans and dihydrofurans with high regioselectivity under mild reaction conditions.
Gold-catalyzed cycloisomerization of alk-4-yn-1-ones
作者:Volker Belting、Norbert Krause
DOI:10.1039/b819704k
日期:——
Depending on the substitution pattern and the solvent, the gold-catalyzed cyclization of alk-4-yn-1-ones 1 affords different oxygen heterocycles under mild reaction conditions. Alkynones with one substituent at C-3 undergo a 5-exo-dig cycloisomerization to substituted furans 2, whereas a 6-endo-digcyclization to 4H-pyrans 3 is observed with substrates bearing two substituents at C-3. In alcoholic solvents