ROM–RCM of azabicycloheptene derivatives—Study of products distribution by the substituent on alkyne

ROM–RCM (ring-opening metathesis and ring-closing metathesis) of azabicyclo[2.2.1]heptene-ynes using the second-generation Grubbs catalyst was investigated. When an azabicycloheptene derivative was exposed to a catalytic amount of a ruthenium carbene complex, pyrrolizidine and indolizidine derivatives were obtained in good yields. The distribution of these products depends on the substituents on the alkyne.

Graphical abstractWhen an azabicycloheptene derivative 1a was exposed to a catalytic amount of a ruthenium carbene complex 3, indolizidine derivative 2a was obtained as a main product along with a fair amount of pyrrolizidine derivative 4a. However, pyrrolizidine derivative 2c was obtained as a major product, when the reaction of 1c was carried out under the same reaction conditions. Figure optionsDownload full-size imageDownload as PowerPoint slide