Heteroaryl Heck reaction pyrazines

Although the heteroaryl Heck reactions of chloropyrazines with pyrrole itself were low-yielding for both mono- and bis-arylation products, better yields were obtained for N-phenylsulfonylpyrrole. Bulkier alkyl substituents on the pyrazine ring promoted the formation of C(3)-substituted pyrroles. The C(3)-substituted pyrrole 64 was the major product (62%) for the coupling of 1 and Al-phenylsulfonylpyrrole, while C(2)-substituted pyrrole 63- was a minor product (15%). 

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