Forging C–C Bonds with Hindered Nucleophiles and Carbonyl Electrophiles: Reactivity and Selectivity of Allylic Tin Reagents/n-BuLi

Synthetic study toward tridachiapyrone B

A convergent approach to the skeleton of tridachiapyrone B is described taking advantage of the desymmetrization of α,α'-dimethoxy-γ-pyrone leading to α-crotyl-α'-methoxy-γ-pyrone in one step. To construct the quaternary carbon of the 2,5-cyclohexadienone of the target, a strategy based on the Robinson-type annulation of an aldehyde derived from α-crotyl-α'-methoxy-γ-pyrone was applied. The grafting of the simplified target's side chain was demonstrated through an oxidative anionic oxy-Cope rearrangement of the tertiary alcohol arising from the 1,2-addition of a 1,3-dimethylallyl reagent to 2,5-cyclohexadienone connected to the α'-methoxy-γ-pyrone motif.

Homologation of halostannanes with carbenoids: a convenient and straightforward one-step access to α-functionalized organotin reagents

A direct, single synthetic homologative transformation of halostannanes into mono- or di-substituted methyl analogues is documented.