Diastereoselective ring-opening aldol-type reaction of 2,2-dialkoxycyclopropanecarboxylic esters with carbonyl compounds. 1. Synthesis of cis 3,4-substituted .gamma.-lactones

1992 ◽  
Vol 57 (26) ◽  
pp. 7126-7133 ◽  
Author(s):  
Shigeru Shimada ◽  
Yukihiko Hashimoto ◽  
Atsushi Sudo ◽  
Masaki Hasegawa ◽  
Kazuhiko Saigo
Keyword(s):  
Carbonyl Compounds ◽  
Ring Opening ◽  
Type Reaction

Diastereoselective ring-opening aldol-type reaction of 2,2-dialkoxycyclopropanecarboxylic esters with carbonyl compounds. 2. Synthesis of cis-2,3-substituted-γ-lactones

Tetrahedron ◽  
1993 ◽  
Vol 49 (8) ◽  
pp. 1589-1604 ◽  
Author(s):  
Shigeru Shimada ◽  
Yukihiko Hashimoto ◽  
Tadamichi Nagashima ◽  
Masaki Hasegawa ◽  
Kazuhiko Saigo
Keyword(s):  
Carbonyl Compounds ◽  
Ring Opening ◽  
Type Reaction

scholarly journals Fates of imine intermediates in radical cyclizations of N-sulfonylindoles and ene-sulfonamides

2015 ◽  
Vol 11 ◽  
pp. 1649-1655 ◽  
Author(s):  
Hanmo Zhang ◽  
E Ben Hay ◽  
Stephen J Geib ◽  
Dennis P Curran
Keyword(s):  
Carbonyl Group ◽  
Ring Opening ◽  
Radical Cyclizations ◽  
Type Reaction ◽  
Primary Products ◽  
Lactam Carbonyl Group ◽  
Lactam Carbonyl ◽  
Imine Reduction ◽  
Derivatives Of

Two new fates of imine intermediates formed on radical cyclizations of ene-sulfonamides have been identified, reduction and hydration/fragmentation. Tin hydride-mediated cyclizations of 2-halo-N-(3-methyl-N-sulfonylindole)anilines provide spiro[indoline-3,3'-indolones] or spiro-3,3'-biindolines (derived from imine reduction), depending on the indole C2 substituent. Cyclizations of 2-haloanilide derivatives of 3-carboxy-N-sulfonyl-2,3-dihydropyrroles also presumably form spiro-imines as primary products. However, the lactam carbonyl group facilitates the ring-opening of these cyclic imines by a new pathway of hydration and retro-Claisen-type reaction, providing rearranged 2-(2'-formamidoethyl)oxindoles.

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