Chemoselective synthesis of dialkyl 2-(tert-butylamino)- 6-methyl-5-trifluoroacetyl-4H-pyran-3,4-dicarboxylates

Abstract

The reaction of tert butyl isocyanide with dialkyl acetylenedicarboxylate affords a highly reactive 1 : 1 intermediate which can be trapped by 1,1,1 trifluoropentane 2,4 dione.

Chemoselective and diastereoselective synthesis of halogenated [1,3] oxazino [2,3‐a] isoquinoline derivatives

“…[32][33][34][35][36] Recently, our research group reported three-component reactions of zwitterionic intermediate derived from dimethyl acetylenedicarboxylate (DMAD) and 3-substituted pyridines with different α-halo ketones that resulted pyrido [2,1b] [1,3]oxazines in high to excellent yields. [37] In an extension of our continuing interest in multicomponent reactions involving zwitterionic species, [38][39][40][41][42] we now describe an efficient procedure for the synthesis of halogenated [1,3] oxazino [2,3a] isoquinoline 8 in high yields via a three-component reaction of isoquinoline 5 with DMAD 6 and different α-halo ketones 7 without formation of any indolizine 9 (Scheme 1).…”