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.

The regioselective C-H bond cleavage/C-O bond formation takes place smoothly upon treatment of 9-(pyridin-2-yl)carbazoles with acetic acid in the presence of a silver salt oxidant under ruthenium catalysis to afford the corresponding C1- and C8-diacetoxylated products. Under similar conditions, the acetoxylation of 2-aryl-1-(pyridin-2-yl)indoles as well as 1-aryl-7-azaindoles can also be conducted efficiently.

The rhodium-catalyzed dehydrogenative coupling of N-pyridylindoles with alkynes proceeds smoothly through rollover cyclometalation to produce indolo[1,2-a][1,8]naphthyridine derivatives. A number of tetra-, penta-, and hexacyclic N-containing heteroaromatics can also be readily constructed in a similar manner. The L-shaped π-conjugated molecules exhibit intense solid-state fluorescence.

a b s t r a c tThe ortho-selective alkenylation of phenyl sulfones with alkynes proceeds effectively in the presence of a cationic Cp*-rhodium(III) catalyst together with an appropriate carboxylic acid involving regioselective CeH bond cleavage directed by the sulfonyl function. An (ortho-alkenylated phenyl) methyl sulfone prepared by this hydroarylation method undergoes palladium-catalyzed a-arylation and subsequent diastereoselective cyclization to directly produce the corresponding thiochromane 1,1-dioxide derivatives.

Rhodium(III)-Catalyzed ortho-Alkenylation Through C-H Bond CleavageDirected by Sulfoxide Groups. -Produced o-alkenylphenyl sulfoxides readily undergo interrupted Pummerer cyclization as well as reduction to afford benzothiophenes [cf. (VI)] and o-alkenylphenyl sulfides [cf. (VII)], respectively. -(NOBUSHIGE, K.; HIRANO, K.; SATOH, T.; MIURA*, M.; Org. Lett. 16 (2014) 4, 1188-1191, http://dx.doi.org/10.1021/ol5000605 ; Dep. Appl. Chem., Fac. Eng., Osaka Univ., Suita, Osaka 565, Japan; Eng.) -S. Adam 31-094