Directed carbonylative (3+1+2) cycloadditions of amino-substituted cyclopropanes and alkynes: reaction development and increased efficiencies using a cationic rhodium system

作者：Shaw Megan H; Whittingham William G; Bower John E^*

来源：Tetrahedron, 2016, 72(22): 2731-2741.

DOI：10.1016/j.tet.2015.08.052

• Rhodium
• Rhodacyclopentanone
• Cycloaddition
• N-Heterocycle
• Catalysis

Urea-directed carbonylative insertion of Rh(I)-catalysts into one of the two proximal C-C bonds of aminocyclopropanes generates rhodacyclopentanone intermediates. These are trapped by N-tethered alkynes to provide a (3+1+2) cycloaddition protocol that accesses N-heterobicyclic enones. Stoichiometric studies on a series of model rhodacyclopentanone complexes outline key structural features and provide a rationale for the efficacy of urea directing groups. A comprehensive evaluation of cycloaddition scope and a 'second generation' cationic Rh(I)-system, which provides enhanced yields and reaction rates for challenging substrates, are presented.

• 出版日期2016-6-2