90909-74-3Relevant academic research and scientific papers
Approaches to the Synthesis of Retronecine from Some Pyrrolidine Precursors
Clare, Brian W.,Ferro, Vito,Skelton, Brian W.,Stick, Robert V.,White, Allan H.
, p. 805 - 824 (2007/10/02)
Procedures are described for the attempted conversion of the pyrrolidine (2) into a bicyclic system that would ultimately lead to retronecine (3). The only molecule to be isolated from these attempts was the epimeric ketone (6), and AM1 and MM2 calculations were used to probe this apparently favoured isomerization. Alternative procedures were then investigated that sought to convert the pyrrolidine (1) into precursors to retronecine, and notable successes were obtained with the addition of the amine (21) to both nitroethene and ethyl 2-diethylphosphonoacrylate. However, not only were these precursors resistant to further transformations into retronecine, but also the problem of epimerization again arose. Consequently, AM1 calculations were again employed, and an X-ray structure determination of ethyl (7R,8R)-7-benzyloxy-1-benzyloxymethyl-5,6,7,8-tetrahydro-3H-pyrrolizine-2-carboxylate (39) is reported. Attempts to convert (39) into a diastereoisomer of retronecine were unsuccessful.
On the Reaction of 2-Pyrrolecarbaldehyde with Hetero-substituted Ethenes
Flitsch, Wilhelm,Lubisch, Wilfried
, p. 1424 - 1435 (2007/10/02)
3H-Pyrrolizines 1 have been obtained from reactions of 2-pyrrolecarbaldehyde with ethenylphosphonates 2 and the phosphane oxide 5, respectively, the ratio of products depending on the structure of the educts.On varying the reaction conditions a controlled synthesis of both isomers 1e/f was achieved.Pyrrolizines, formed in a reaction of 2-pyrrolecarbaldehyde with ethenyl phenyl sulfone (3), could not be isolated since the reaction proceeded to give more complex pyrrolizine derivatives and the cyclazine 11.A mechanism is proposed for this multistep reaction.N-Alkylatio n of 2-pyrrolecarbaldehyde with dihaloalkanes has been carried out using phase transfer catalysis.
