Cine Substitution of Arenes Using the Aryl Carbamate as a Removable Directing Group
摘要:
An efficient and controlled means to achieve a rare cine substitution of arenes is reported. The methodology relies on the strategic use of aryl O-carbamates as readily removable directing groups for arene functionallzation. The removal of aryl carbamates is achieved by employing an airstable Ni(II) precatalyst, along with an inexpensive reducing agent, to give synthetically useful yields across a range of substrates. The net cine substitution process offers a new strategy for analogue synthesis, which complements the well-established logic for achieving arene functionalization by ipso substitution.
Herein we describe an iron-catalyzed borylation of alkenyl and arylcarbamatesthrough the activation of a C–O bond. This protocol exhibits high efficiency, a broad substrate scope, and the late-stage borylation of biorelevant compounds, thus providing potential applications in medicinal chemistry. Moreover, this method enables orthogonal transformations of phenol derivatives and also offers good opportunities
在本文中,我们描述了通过C-O键的活化,铁催化的烯基和芳基氨基甲酸酯的硼酸酯化反应。该方案显示出高效率,广泛的底物范围以及生物相关化合物的后期硼化,因此在药物化学中提供了潜在的应用。而且,该方法能够使酚衍生物进行正交转化,并且还为合成多取代的芳烃提供了良好的机会。初步的机理研究表明,通过自由基途径的Fe II / Fe III催化循环可能与反应有关。
C–O Bond Silylation Catalyzed by Iron: A General Method for the Construction of Csp<sup>2</sup>–Si Bonds
The iron-catalyzed construction of Csp2–Si bonds via unreactive C–O bonds possesses a challenging topic in organic chemistry. Herein we report an iron-catalyzed silylation of aryl and alkenylcarbamates via C–O bond activation. This protocol features high efficiency and a broad substrate scope, enabling the late-stage silylation of biorelevant compounds and thus providing a good method to access valuable
The directed ortho metalation connection to aryl-aryl cross coupling.A general regiospecific synthesis of phenanthrols
作者:J.-m. Fu、M.J. Sharp、V. Snieckus
DOI:10.1016/s0040-4039(00)80786-8
日期:1988.1
A general directed metalation-based cross coupling synthesis of phenanthrols 4 has been developed (Scheme 1); reactions of derived triflates and carbamates 10 lead to a variety of substituted phenanthrenes 7 → 12 (Scheme 2).
Nickel(0)-catalyzed cross coupling of aryl O-carbamates and aryl triflates with Grignard reagents. Directed ortho metalation-aligned synthetic methods for polysubstituted aromatics via a 1,2-dipole equivalent
The first Ni(0)-catalyzed cross-coupling reactions of aryl O-carbamates and aryl triflates with Grignard reagents (Scheme I) to give diversely polysubstituted aromatics 2d and 2e (Table I) which feature regiospecificity based on directed ortho metalation (carbamate), minimal beta-hydride elimination (triflate), and dependence on steric and electronic effects are described.
FU, J. -M.;SHARP, M. J.;SNIECKUS, V., TETRAHEDRON LETT., 29,(1988) N 43, C. 5459-5462