Chemodivergence in Pd-catalyzed desymmetrization of allenes: enantioselective [4+3] cycloaddition, desymmetric allenylic substitution and enynylation
Pengfei Luo, Long Li, Xinfang Mao, Zheng Sun, Yingcheng Wang, Fangzhi Peng, Zhihui Shao
Abstract
-aminophenols, the racemization of the [4+3] cycloaddition products is effectively suppressed. Mechanistic studies reveal that elusive Pd-catalyzed enantioselective intramolecular allenylic substitution rather than intermolecular allenylic substitution is the enantio-determining step in this cycloaddition. By tuning the ligands, a Pd-catalyzed enantioselective desymmetric allenylic substitution leading to linear axially chiral tri-substituted allenes or a Pd-catalyzed tandem desymmetric allenylic substitution/β-vinylic hydrogen elimination (formal enynylation) leading to multi-functionalized 1,3-enynes is achieved chemodivergently.
Topics & Concepts
Enantioselective synthesisCycloadditionDesymmetrizationSynthonChemistryIntramolecular forceCatalysisAlleneStereochemistryCombinatorial chemistryMedicinal chemistryOrganic chemistryCatalytic Alkyne ReactionsAxial and Atropisomeric Chirality SynthesisCatalytic C–H Functionalization Methods