136764-82-4Relevant academic research and scientific papers
(±)-cis-4a-alkyl-1,3,4,4a,9,9a-hexahydro-2H-carbazol-2-ones by domino nitro reduction-aza-Michael addition to enones
Barrios-Perez, Carlos,Bunce, Richard A.,Embrey, Samuel J.
, (2022/01/11)
A domino nitro reduction-aza-Michael addition sequence has been 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 (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 has been extended to a synthesis of (±)-cis-4a-alkyl-1,3,4,4a,9,9a-hexahydro-2H-carbazol-2-ones 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 give a more stable chair-like enol that tautomerized to the target heterocycle.
