Base-Promoted Tandem Synthesis of 2-Substituted Indoles and N-Fused Polycyclic Indoles

Masters of Mediation: MN(SiMe3)2 in Functionalization of C(sp3)−H Latent Nucleophiles

“…In this vein, very recently, Lin, Walsh, Li and co‐workers unveiled a unique route to C2‐substuited indoles 25 via 5‐endo‐dig cyclisation/1,3′‐acyl migration and accessing N ‐fused polycyclic indoles 26 with three new stereogenic centers via 5‐endo‐dig cyclisation/Michael addition with a loss of aromaticity (Scheme 13). [44] The reaction is feasible with LiN(SiMe 3 ) 2 whereas NaN(SiMe 3 ) 2 and KN(SiMe 3 ) 2 showed reduced proficiency in yielding the desired products. In few cases, the combination of KN(SiMe 3 ) 2 with an excess of 18‐crown‐6 outperformed LiN(SiMe 3 ) 2 .…”

Base‐Promoted Structural Rearrangement of Ynamide and Simultaneous N‐Desulfonylation

“…[4] 2-Alkynyl aniline derivatives have been utilized in the presence of transition metals or Lewis acids for structural rearrangement. [5] Transition metals or Lewis acids initially activate the alkyne to increase its electrophilicity for further cyclization with the available ortho-substituted nucleophilic aniline counterpart to produce highly reactive intermediates in these transformations. Simultaneously, they dissociate the nitrogen substituent [Me, benzyl allyl, propargyl, acyl, silyl, alkoxyalkyl, sulfonyl, B(OR) 2 , etc.]…”