Direct Umpolung Morita-Baylis-Hillman like α-Functionalization of Enones via Enolonium Species.

Herein we report on the umpolung of Morita-Baylis-Hillman type intermediates and application to the α-functionalization of enone C-H bonds. This reaction gives direct access to α-chloro-enones, 1,2-diketones and α-tosyloxy-enones. The latter are important intermediates for cross-coupling reaction and, to the best of our knowledge, cannot be made in a single step from enones in any other way.

Rhodium(iii)-catalyzed C-H activation at the C4-position of indole: switchable hydroarylation and oxidative Heck-type reactions of maleimides.

A Rh(iii)-catalyzed C-H activation of indole at the C4-position leading to novel and switchable functionalization has been reported by employing a weakly co-ordinating COCF3 group as a directing group. An additive plays an important role in switching the selectivity between 1,4-addition products and Heck-type products. An acid additive led to the formation of 1,4-addition products whereas a base additive promotes the formation of Heck-type products.

Weak Directing Group Steered Formal Oxidative [2+2+2]-Cyclization for Selective Benzannulation of Indoles.

A double C-H activation and double insertion process to achieve the synthesis benzo[e]indole frameworks has been disclosed. This type of benzannulation is directed by a trifluoromethylketone moiety, which is easy to install on the indole C3-position. Overall the reaction takes places as an oxidative cyclization of two alkynes with the C4-C5 position of indole.