Photochemistry of novel azabicyclic compounds; concerning the site- and regio-selectivity of di-π-methane transformations of 5,6-benzo-2-azabarrelenes

Oxa-di-π-methane Photochemical Rearrangement of Quinuclidinones. Synthesis of Pyrrolizidinones

“…The synthetic potential of the photochemical ODPM rearrangement of various all-carbon bicyclo[2.2.2]octenones to produce bi- and tricyclopentanoid compounds has been illustrated by several groups. , When we first designed our original photoprecursor, 1 , we wondered if the lone pair of electrons on the nitrogen would interfere with the photochemistry, as it is known that amines can undergo photoactivated single-electron transfer (SET) reactions 4e. To our knowledge, the majority of nitrogen-containing photoprecursors have been studied in either the di-π-methane rearrangement where the nitrogen did not participate in the rearrangement (as shown in Scheme , eq 1) 2a,e,4a,b or the aza-di-π-methane rearrangement (Scheme , eqs 2 and 3). 2a,4d,e The oxa-di-π-methane rearrangement of the bicyclo-hydrazide (Scheme , eq 4) is a rare example of a nitrogen-containing bicyclic system being rearranged via the ODPM reaction 4f 2 …”