Abstract
A general catalyzed direct C−H functionalization of s-tetrazines is reported. Under mild reaction conditions, N-directed ortho-C−H
activation of tetrazines allows the introduction of various functional
groups, thus forming carbon–heteroatom bonds: C−X (X=I, Br, Cl) and C−O.
Based on this methodology, we developed electrophilic mono- and poly-ortho-fluorination of tetrazines. Microwave irradiation was optimized to afford fluorinated s-aryltetrazines,
with satisfactory selectivity, within only ten minutes. This work
provides an efficient and practical entry for further accessing highly
substituted tetrazine derivatives (iodo, bromo, chloro, fluoro, and
acetate precursors). It gives access to ortho-functionalized aryltetrazines which are difficult to obtain by classical Pinner-like syntheses.
activation of tetrazines allows the introduction of various functional
groups, thus forming carbon–heteroatom bonds: C−X (X=I, Br, Cl) and C−O.
Based on this methodology, we developed electrophilic mono- and poly-ortho-fluorination of tetrazines. Microwave irradiation was optimized to afford fluorinated s-aryltetrazines,
with satisfactory selectivity, within only ten minutes. This work
provides an efficient and practical entry for further accessing highly
substituted tetrazine derivatives (iodo, bromo, chloro, fluoro, and
acetate precursors). It gives access to ortho-functionalized aryltetrazines which are difficult to obtain by classical Pinner-like syntheses.
Ring me up: The selective palladium-catalyzed ortho-C−H halogenation of s-tetrazine has been achieved. Fast fluorination is performed within 10 minutes by using N-fluorobenzenesulfonimide
(NFSI). By this method, di-, tri-, and tetrahalogenated aryltetrazines
are accessible in a straightforward manner.
(NFSI). By this method, di-, tri-, and tetrahalogenated aryltetrazines
are accessible in a straightforward manner.
0 件のコメント:
コメントを投稿