Reaction Discovery Using Neopentylene-Tethered Coupling Partners: Cycloisomerization/Oxidation of Electron-Deficient Dienynes

A rhodium-catalyzed cycloisomerization and oxidation of tethered dienynes for the synthesis of indanes is described. An auxiliary fragmentation/olefination method (also described herein) provides novel access to tethered alkyne-dienoate substrates. The reported method circumvents current limitations in and expands the scope of inverse-demand Diels–Alder-type cycloadditions. Traditional discovery substrates involving malonate-, ether-, and sulfonamide-based tethers are problematic in the current methodology, underscoring the unique virtue of neopentylene-tethered substrates for reaction discovery

Six-Step Synthesis of Alcyopterosin A, a Bioactive Illudalane Sesquiterpene with a <i>gem</i>-Dimethyl­cyclopentane Ring

Strategic pairing of ring openings and cycloisomerization provides rapid and efficient “open and shut” entry into sparsely functionalized illudalanes, as exemplified here in the context of a six-step synthesis of alcyopterosin A. Key steps include a tandem ring-opening fragmentation/olefination process for preparing a neopentyl-tethered 1,6-enyne, ring-opening olefination telescoped with alkyne homologation, and Rh-catalyzed oxidative cycloisomerization