New phosphorus self-assembling ligands for the tandem hydroformylation–Wittig olefination reaction of homoallylic alcohols — A key step for stereoselective pyran synthesis
摘要:
New self-assembled phosphorus ligands are synthesized and used in the rhodium complex catalyzed hydroformylation-Wittig reaction of homoallylic olefins under optimized condition. A subsequent oxa-Michael intramolecular reaction yields beta-pyran derivatives (conversion and diastereoselectivity up to 99%). (C) 2014 Elsevier B.V. All rights reserved.
rhodium-catalyzed asymmetric N2-C5 allylation of indazoles with dienyl allylic alcohols under mild conditions. In the presence of a Rh/(P/olefin) catalyst and formic acid, chiral N2-C5 allylic indazoles were formed in good yields with excellent enantioselectivities (up to 97% ee). The mechanism proceeds through an elusive intermediate Int B, which represents a challenging task on asymmetricallylic substitution