Oxidative Cyclization of Sulfamates onto Pendant Alkenes

Abstract

This communication discloses the first examples of aza-Wacker cyclizations of sulfamate esters. Within the realm of related cyclization reactions, this protocol is differential in that it forms six-membered rings in good yield and uses catalytic amounts of palladium(0) rather than palladium(II) salts. These reactions scale well, and their products are demonstrated to be valuable synthetic intermediates.Letter pubs.acs.org/OrgLett

Salient features of the aza-Wacker cyclization reaction

“…16). 16 The sulfamate auxiliary could be conveniently appended to a variety of alcohols and cyclized onto diverse pendant alkenes. The reaction utilizes the unusual reagent combination of Pd 2 (dba) 3 along with Cu(OAc) 2 under 1 atm of O 2 .…”

Highly Regio- and Diastereoselective Tethered Aza-Wacker Cyclizations of Alkenyl Phosphoramidates

“…Tethered aza-Wacker cyclization reactions are enabling because they free the synthetic practitioner from the constraint of needing a pre-existing C–N bond in order to forge a new one. , …”

Tethered Silanoxymercuration of Allylic Alcohols

“…The family of organomercurials has earned an unfortunate reputation, largely due to the actions of a minority of its members. , Nevertheless, the majority of higher-order organomercurial compounds are crystalline, air-stable, and, when treated with appropriate respect, no more dangerous than most chemicals encountered in the organic laboratory . The C–Hg linkage is essentially covalent, making it a most unique and versatile organometallic bond. − Our laboratory is deeply invested in the field of tethered olefin functionalization reactions. − In such reactions, a nucleophilic auxiliary (the “tether”) is appended to an alcohol or amine and then cyclized onto a pendant alkene. Here, we disclose our most recent contribution to this area: a cyclization reaction of allylic silanols into cyclic silanediol mercury chloride compounds.…”