Organocatalytic Enantioselective Synthesis of Bicy-clo[2.2.2]octenones via Oxaziridinium Catalysed ortho-Hydroxylative Phenol Dearomatization

Hydroxylative dearomatization reactions of phenols (HPD) offer an efficient way to assemble complex, biologically relevant scaffolds. Despite this, enantioselective hydroxylative phenol dearomatizations for the construction of bicy-clo[2.2.2]octenones are classically limited to stoichiometric chiral reagents, and a practical, enantioselective catalytic method has remained elusive. Herein, we describe a highly enantioselective, organocatalytic tandem o-HPD-[4+2] reaction. Our methodology utilizes a chiral oxaziridinium organocatalyst that affords high enantioselectivity for a wide range of phenol substitution patterns, and was applied in the synthesis of (+)-biscarvacrol and bis(2,6-xylenol). The practicality of our conditions were demonstrated at gram-scale, using an amine precatalyst that can be accessed in a single synthetic step.