Embrey, Samuel J.; Barrios-Perez, Carlos; Bunce, Richard A. published the artcile< (±)- cis-4a-alkyl -1,3,4,4a,9, 9a-hexahydro-2H -carbazol-2-ones by domino nitro reduction-aza-Michael addition to enones>, Category: esters-buliding-blocks, the main research area is cis alkyl hexahydro carbazolone preparation; enone domino nitro reduction aza Michael addition.
A domino nitro reduction-aza-Michael addition sequence was investigated for α,β-unsaturated ketones and compared with the analogous reaction for conjugated esters. As expected, six-membered ring closures of ketones did not proceed as well as for esters (<60% vs. >85%) due to the greater inherent reactivity of the ketones. This problem was minimized by performing the cyclization at lower temperature for a shorter time. The process had been extended to a synthesis of (±)-cis-4a-alkyl-1,3,4,4a,9,9a-hexahydro-2H-carbazol-2-ones I [R = Me, Et, n-Pr, Bn] with good yields (65%-86%). While the rigidity of the system and closure of the smaller five-membered ring created some strain in the products, yields were acceptable. The cis ring junction resulted from axial attack to gave a more stable chair-like enol that tautomerized to the target heterocycle.
Journal of Heterocyclic Chemistry published new progress about Aza-Michael reaction. 30095-98-8 belongs to class esters-buliding-blocks, and the molecular formula is C9H9NO4, Category: esters-buliding-blocks.
Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics