Formation of α-dialkylamino alkyllithium intermediates in the reaction of N,N-dialkylamides with PhMe2SiLi followed by a second lithium reagent, and their alkylation, fragmentation, cyclisation and rearrangement by proton transfer

Tertiary amides (RCONMe2) react with PhMe2SiLi, followed by a second lithium reagent NuLi, to give alpha-dialkylamino alkyllithium intermediates R(Me2N)CLiNu that undergo protonation 2 --> 3, alkylation 2a --> 3ab, beta-elimination 5 --> 6, intramolecular attack on an isolated double bond 9 --> 10, intramolecular proton transfer 12, 17 and 22 (arrows), and fragmentation 28 and 34 (arrows), depending upon the structures of the various components R and Nu.