Intramolecular [1 + 2] and [3 + 2] cycloaddition reactions of cyclopropenone ketals.

ABSTRACT: The first intramolecular thermal reactions of cyclopropenone ketals are reported and the work examined substrates tethered to an electron-deficient olefin bearing a single electron-withdrawing substituent. Whereas the intermolecular variants of the reactions provide only the products of an endo-selective [1 + 2] cycloaddition or a carbonyl addition reaction of a thermally generated pi-delocalized singlet vinylcarbene, the intramolecular variants provide either [1 + 2] or [3 + 2] cycloadducts in reactions that depend on the reaction conditions, the alkene-activating substituent, and the nature of the tethering. In addition to providing key mechanistic insights into the thermal [3 + 2] cycloaddition reaction for such substrates, they were also found to proceed under conditions that reflect t

SUBMITTER: Patel PR 

PROVIDER: S-EPMC2892887 | biostudies-literature | 2010 Jun

REPOSITORIES: biostudies-literature