Synthesis of 2,3-disubstituted pyrroles from 3,N-dilithio-N-(tert-butyldimethylsilyl)-2-buten-1-amine.

N-(Trialkylsilyl)allylamines can be deprotonated at the cis-vinylic position to yield 3,N-dilithio-N-(trialkylsilyl)allylamines under mild conditions. N-(Trialkylsilyl)allylamines with terminal alkyl substituents were reported not to form dianions under the same conditions. During our investigations we found that N-(tert-butyldimethylsilyl)-2-buten-1-amine (1) is deprotonated under the reaction conditions reported in the literature, but the resulting dianion is quenched by ethereal solvents. Consequently, new reaction conditions were developed that allow the generation of stable dianions from allylamines with terminal alkyl substituents. Thus, 2,3-disubstituted pyrroles hitherto unattainable via this methodology were formed from 3,N-dilithio-N-(tert-butyldimethylsilyl)-2-buten-1-amine (2) and various carbonyl electrophiles in good yields.