Haloiminolactonization of cyclopentene α,α-dichlorocarboxamides. Tandem rearrangement of iminolactones in epoxylactones.

Valiullina, Z.; Akhmet'yanova, V.; Ivanova, N.; Erastov, A.; Miftakhov, M.; Meshcheryakova, E.

Electrophilic cyclization initiated by NBS and I of 2,2-dichloro-2-[(1 R,5 S)- and 2,2-dichloro-2-[(1 S,5 R)-5-hydroxy-2-cyclopent-2-en-1-yl]- N-[(1 R)-1-phenylethyl]acetamides was investigated. Stable under conditions of chromatography on SiO bicyclic iminoesters, (2 Z,3a S,4 S,6 S,6a S)-6-bromo-3,3-dichloro- and (2 Z,3a S,4 S,6 S,6a S)-3,3-dichloro-6-iodo-2-{[(1 R)-1-phenylethyl]imino}hexahydro-2 H-cyclopenta[ b]furan-4-ols were isolated and characterized, and a possible version was suggested of their step-by-step recyclization transformations. The halocyclization of carboxamides in water-organic mixtures afforded bicyclic epoxylactones (1a R,2a S,5a S,5b S)- and (1a S,2a R,5a R,5b R)-5,5-dichlorohexahydro-4 H-oxireno[3,4]cyclopenta-[1,2- b]furan-4-ones, whose reductive dechlorination proceeded stepwise with successive removal of Cl atoms and led to the formation of (1a R,2a S,5a S,5b S)- and (1a S,2a R,5a R,5b R)-hexahydro-4 H-oxireno[3,4]cyclopenta-[1,2-b]furan-4-ones.

ELECTROPHILIC addition reactions; CYCLOPENTENES; LACTONES; RING formation (Chemistry); CARBOXAMIDES

Russian Journal of Organic Chemistry, 2015, Vol 51, Issue 11, p1524

1070-4280

Academic Journal

10.1134/S1070428015110020