Ortho- and Para-Selective Ruthenium-Catalyzed C(sp2)–H Oxygenations of Phenol Derivatives
摘要:
Versatile ruthenium catalysts allowed for efficient direct oxygenations of aryl carbamates under remarkably mild reaction conditions. In addition to chelation-assisted C-H activation, the optimized ruthenium catalyst proved amenable to para-selective hydroxylations of anisoles without Lewis basic directing groups.
N-Protected 1,2-Oxazetidines as a Source of Electrophilic Oxygen: Straightforward Access to Benzomorpholines and Related Heterocycles by Using a Reactive Tether
A hitherto unknown reactivity of a strained four‐membered heterocycle, 1,2‐oxazetidine, is reported. When reacted with organometallic compounds, this reagent provides electrophilicoxygen with a nitrogen‐terminated two‐carbon‐atom tether. The synthetic versatility of the products obtained was demonstrated in various transformations, leading to efficient synthesis of six‐, seven‐, and eight‐membered