Dedicated to Professor Masahiro Murakami.
Abstract
Photochemical cascade (domino) reactions provide a unique opportunity for the construction
of complex molecular architectures. Specifically, an intramolecular ortho photocycloaddition of 7-(alkenyloxy)-indanones triggers a sequence of consecutive
reactions that can lead in a single operation to the complete skeleton of two important
classes of sesquiterpenes: protoilludanes and prezizaenes. In the former case, two
transformations follow the initial photocycloaddition, while in the latter case, there
are three consecutive transformations, two of which are initiated by a photon. Remarkably,
the reaction cascades proceed with exquisite diastereoselectivity, generating three
(protoilludane) or five (prezizaene) stereogenic centers with defined relative configurations.
1 Introduction
2 First Encounter and Initial Studies
3 Protoilludane-Type Sesquiterpenes
4 Prezizaene-Type Sesquiterpenes
5 Enantioselectivity
6 Perspective and Summary
Key words
cycloaddition - domino reaction - electrocyclic reactions - photochemistry - stereoselective
synthesis - terpenoids