Potassium carbonate, functional group tolerance

Polyfunctionalized pyrrole 37 was prepared by Punniyamurthy from 1,3-enyne 35 and aniline derivative 36 in the presence of iodine and potassium carbonate. The reaction proceeds at room temperature under air with good functional group tolerance. Additionally, the sequence can be carried out with aqueous ammonia in place of 36 to afford unprotected pyrroles in moderate yield (130L4996). 

Many types of functional groups are tolerated in a Suzuki reaction, and the yields are often good to very good. The presence of a base, e.g. sodium hydroxide or sodium/potassium carbonate, is essential for this reaction. The base is likely to be involved in more than one step of the catalytic cycle, at least in the transmetal-lation step. Proper choice of the base is important in order to obtain good results." In contrast to the Heck reaction and the Stille reaction, the Suzuki reaction does not work under neutral conditions. 

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