Ring‐Closure Reactions of ortho‐Vinyl‐tert‐anilines and (Di)Aza‐Heterocyclic Analogues via the tert‐Amino Effect: Recent Developments

Abstract

Organic chemistry Z 0200Ring-Closure Reactions of ortho-Vinyl-tert-anilines and (Di)Aza-Heterocyclic Analogues via the tert-Amino Effect: Recent Developments -[about 30 refs.]. -(MATYUS*, P.; ELIAS, O.; TAPOLCSANYI, P.; POLONKA-BALINT, A.; HALASZ-DAJKA, B.; Synthesis 2006, 16, 2625-2639; Dep. Org. Chem., Semmelweis Univ., H-1095 Budapest, Hung.; Eng.) -Lindner 45-242

Total synthesis of (+)-lentiginosine via a key Au catalysis

“…We have recently reported a formal [4+2] approach for the synthesis of piperidin-4-ones [13] via a key gold catalysis [14][15][16][17][18][19][20][21][22][23]. In this two-step sequence (Scheme 1), a secondary amine is initially alkylated with but-3-ynyl tosy late in a S N 2 reaction; subsequent m-CPBA oxidation of the formed tertiary amine into the corresponding N-oxide is followed by Au(I)-catalyzed intramolecular oxidation of the alkyne moiety, yielding an -oxo gold carbene intermediate (i.e., A); a formal carbene insertion into the CH bond  to the nitrogen atom presumably via sequential hydride migration and cyclization leads to an overall 4+2 annulation between a secondary amine (a C1 + N1 unit) and a but-3-ynyl moiety (a C4 unit).…”