The Synthesis of Aracemic 4-Substituted Pyrrolidinones and 3-Substituted Pyrrolidines. An Asymmetric Synthesis of (-)-Rolipram
Conjugate additions of RCuCNLi to the chiral α,β-unsaturated lactam 4 gives almost exclusive exo addition - a reversal in stereochemistry when cuprates were added to chiral lactam 1.The lactams 5 were transformed into 4-substituted pyrrolidinones 8 via a three-step sequence which involved decarbalkoxylation, silane reduction and metal-ammonia benzylamine cleavage.The chemical yields as well as the enantiomeric purity were very high for this process.As an example of the usefulness of this scheme, the antidepressant (-)-Rolipram was prepared in good overall yield.Furthermore, the bicyclic lactams 6 were readily transformed, using alane as the reducing agent, to 3-substituted pyrrolidines 11.Absolute configurations of 8 and 11 were confirmed by comparison with literature assignments which also gave strong support to the facial addition of the cuprates to 4.
Meyers, A. I.,Snyder, Lawrence
p. 36 - 42
(2007/10/02)
More Articles about upstream products of 145548-97-6
Get Best Price for145548-97-6(3S,6S,7R,7aR)-7-(3-Cyclopentyloxy-4-methoxy-phenyl)-5-oxo-3-phenyl-hexahydro-pyrrolo[2,1-b]oxazole-6-carboxylic acid benzyl ester