Stereoselective Formation oftrans-Decalin andcis-Decalin Skeletons via Hydroxy Group Directed Cyclization Induced by Samarium(II) Iodide

Sequenced Reactions with Samarium(II) Iodide. Domino Epoxide Ring-Opening/Ketyl Olefin Coupling Reactions

“…Our earlier work and results reported from other laboratories have demonstrated that samarium(II) iodide also promotes intramolecular ketyl olefin cyclization processes (eqs 1 and 2). These reactions occur with high diastereoselectivity about the newly formed carbon−carbon bonds.…”

Sequencing Reactions with Samarium(II) Iodide

“…The powerful influence of appropriately positioned hydroxyl groups in facilitating intermolecular ketyl olefin coupling reactions and controlling stereochemistry has been alluded to previously (cf. eqs [28][29][30]. The significant influence of free hydroxyl groups on intramolecular coupling reactions has been examined with equal success.…”

“…The significant influence of free hydroxyl groups on intramolecular coupling reactions has been examined with equal success. 28 Even in the absence of promoters such as HMPA, these reactions proceed smoothly at low temperatures, providing high yields of the desired products with excellent diastereoselectivity in some cases (eqs 52-54). In fact, the addition of HMPA decreased the diastereoselection in the reaction, and protection of the hydroxy group as a tertbutyldimethylsilyl ether resulted in the complete recovery of starting material.…”

“…eqs 28−30). The significant influence of free hydroxyl groups on intramolecular coupling reactions has been examined with equal success . Even in the absence of promoters such as HMPA, these reactions proceed smoothly at low temperatures, providing high yields of the desired products with excellent diastereoselectivity in some cases (eqs 52−54).…”

Use of Lewis Acids in Free Radical Reactions

“…Three important reaction classes will be discussed. [52] The stereochemistry is best explained by the sixmembered ring chelate 56 r. [52±54] One typical example is reported in Equation (12).…”