It adds up to 4! Thiophenes and thiazoles can be arylated in the 4‐ rather than the expected 5‐position in a new CH functionalization reaction (see scheme; TEMPO: 2,2,6,6‐tetramethylpiperidine‐N‐oxyl). The boronic acid proved to be the key to achieving the otherwise difficult C4 selectivity. The method was applied to a concise synthesis of a key pharmacological structure with potential for treatment of Alzheimer's disease.

Indoles are not indolent: Various indoles react with arylboronic acids chemodivergently. C-H arylation of free indole and N-methylindole gives the corresponding C(2)-arylated indoles A whereas N-acylated, N-benzoylated, and N-Boc-protected indoles provide the corresponding arylcarboaminoxylated products B with excellent diastereoselectivity in good to excellent yields.

No abstract

Direct C-H phenylation of 2-ethylthiophene and 2-chlorothiophene with PhPdI(bipy) complex to form either the corresponding 4-phenyl or 5-phenylthiophene derivative is studied under stoichiometric conditions using various Lewis acids as additives. It is shown that reactions occur via the corresponding cationic Pd complex (PhPdbipy(+)) and that the counteranion determines the regioselectivity. High-level DFT calculations reveal that C-C bond formation occurs via a carbopalladation pathway and not via electrophilic palladation. These calculations give some indications regarding the regioselectivity of the thiophene arylation.

Excellent stereoselectivity is obtained in the synthesis of biologically interesting 1,2,3‐trisubstituted indanes B by the reaction of readily prepared 3‐substituted indenes A with commercially available arylboronic acids by using various TEMPO derivatives as external oxidants and Pd(OAc)2 as a catalyst. The anti,anti isomers are formed and reactions occur stereospecifically under mild conditions.