Rhodium(III)-Catalyzed Ortho-Alkenylation through C–H Bond Cleavage Directed by Sulfoxide Groups

Abstract

The rhodium-catalyzed ortho-alkenylation of phenyl sulfoxides using alkenes or alkynes as substituent sources proceeds efficiently through sulfoxide group directed C-H bond cleavage to produce the corresponding o-alkenylphenyl sulfoxides. The products readily undergo interrupted Pumerer cyclization as well as reduction to afford benzothiophenes and o-alkenylphenyl sulfides.

C−H Coupling Reactions Directed by Sulfoxides: Teaching an Old Functional Group New Tricks

“…Satoh and Miura exploited as ulfoxide directing group to mediate the Rh-catalyzed ortho CÀHa lkenylation of aryl sulfoxides 53 using electron-deficient alkenes or aryl alkynes (Scheme 20). [35] TheC ÀHa lkenylation using alkenes pro-ceeds by coordination of the sulfoxide oxygen atom to Rh III (see intermediate 54;Scheme 20 C). This enables subsequent cyclometalation to give intermediate rhodacyle 55,w hich then undergoes alkene insertion.…”

“…b-Hydride elimination furnishes the alkenylaryl sulfoxide products 56,and oxidation of Rh I to Rh III by Ag 2 CO 3 closes the catalytic cycle. [35] In arelated transformation, Jeganmohan and Padala used as ulfoxide group to direct the Ru II -catalyzed C À Ha lkenylation of aryl sulfoxides 53 with aryl alkynes as the crosscoupling partner (Scheme 21). [36] This Ru-catalyzed system is believed to operate solely at the Ru II oxidation state (Scheme 21 C).…”

Rhodium-catalyzed direct ortho-alkenylation of phenyl sulfones with alkynes utilizing sulfonyl function as modifiable directing group

“…Other sulfonyl groups containing no pyridyl moiety have, to our knowledge, never been utilized as effective directing groups. During our continuous studies of rhodium-catalyzed CeH functionalization, 1t we succeeded in finding that simple phenyl sulfones undergo direct alkenylation upon treatment with internal alkynes 2,6 in the presence of a rhodium catalyst through CeH bond cleavage directed by their sulfonyl group to produce ortho-alkenylated phenyl sulfones (Scheme 1). In these reactions, simple alkyl-and aryl sulfonyl functions without any pyridyl group could act as effective directing groups.…”

1,2‐Thiazines: One‐Pot Syntheses Utilizing Mono and Diaza Analogs of Sulfones

“…Finally,arhodium-catalyzed CÀHb ond functionalization was demonstrated. [25][26][27] Again, 4p was used as starting material, and in this case, the aryl group at C3 of the heterocycle was functionalized. With butyl acrylate (9), as mooth ortho-alkenylationo ccurred, providing 7c in 74 % yield.…”