Regioselectivity of rhodium(II)-catalyzed decomposition of 1-alkyl-1-(diazoacetyl)alkenes. Synthesis of 2-alkyl-2-cyclopentenones and 2-alkylidenecyclopentanones
摘要:
The synthesis of 1-alkyl-1-(diazoacetyl)alkenes and their dirhodium tetraacetate catalyzed transformation into 2-cyclopentenones and 2-alkylidenecyclopentanones are described. The competitive, intramolecular carbon-hydrogen insertion at two gamma-centers is discussed.
Rings of five and six: Donor alkenyl rhodiumcarbenoidsgeneratedfrom 3,3‐dimethylcyclopropenylcarbinols exhibit high reactivity in intramolecular CHinsertions. The reactions proceed under remarkably mild conditions, tolerate the presence of the free hydroxy group, and afford an efficient and stereoselective access to a variety of functionalized carbocycles and oxygen heterocycles.