RETRACTED: Asymmetric synthesis of highly enantioenriched 2-substituted piperidines and 6-substituted piperidine-2-ones by a combination enantioselective hydrazone allylation with ring closing metathesis

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy).This article has been retracted at the request of the corresponding author. The corresponding author prepared a series of cinchonine derivatives and found that the structure of PCA, which was a major compound, was mistakenly assigned. The synthetic routes, physical and spectroscopic data for the products are valid. As a result the corresponding author withdraws this publication.