Unified syntheses of cavicularin and riccardin C: addressing the synthesis of an arene adopting a boat configuration.

Concise syntheses of the natural products cavicularin (ten steps) and riccardin C (seven steps) are reported. Key features of the new synthetic route are a convergent strategy to assemble acyclic precursors and a sequence of regioselective reduction and halogenation steps to facilitate Wittig macrocyclisation and transannular ring contraction reactions.

Effect of sulfide structure on enantioselectivity in catalytic asymmetric epoxidation of aldehydes: mechanistic insights and implications.

Bridged bicyclic sulfide 1 was originally found to provide high levels of asymmetric induction in sulfur ylide-mediated epoxidations. This sulfide possesses chirality in the [2.2.

Formal intramolecular [5 + 2] photocycloaddition reactions of maleimides: a novel approach to the CDE ring skeleton of (-)-cephalotaxine.

A concise approach to the cephalotaxine CDE ring skeleton based on the intramolecular formal [5 + 2] photocycloaddition of cyclopentenyl-substituted maleimides is described. An investigation of the diastereoselectivity afforded by various protected alkoxy groups demonstrated that the best selectivity (3.5:1) was afforded by the free hydroxyl group, strongly suggesting a hydrogen-bonded excited state.