84958-12-3Relevant academic research and scientific papers
Acid-catalysed Cyclizations of B-Seco-steroidal Intermediates
Kasturi, T. R.,Reddy, B. Madhava,Sarkar, A.
, p. 807 - 812 (2007/10/02)
A systematic study of acid-catalysed cyclization reactions of the seco-diones (1) with different acidic reagents and solvents has been carried out.The results indicate the role of protic and aprotic solvents in deciding the nature of the product.Protic solvents favour the formation of isomeric exo-and endo-bicyclooctane-6,8-diones (2) and (3), while aprotic solvents preferentially yield the steroidal pentaenones (4).The MeOH-HCl reagent provides a general synthetic method for the said bicyclic systems.The formation of bicyclic copounds is precluded in p-tosic acid-benzene even when the isomerization leading to pentaenone formation is prevented on structural grounds.With dioxane-HCl reagent both the competitive pathways are feasible, though the rate of the normal cyclization to yield pentaenones (4) is much faster than the enol-addition leading to bicyclic compounds (2) and (3).When the former is forbidden on steric grounds, the latter pathway yields the corresponding products.
