ASYMMETRIC ROUTES TO SUBSTITUTED PIPERIDINES

An overview of the main asymmetric routes to substituted piperidines i s presented, A wide range of synthetic strategies have been developed, because of the ubiquitous nature of the piperidine sub-unit in natura l products, and because of the biological properties of natural and sy nthetic piperidine derivatives. This review concentrates on general me thodologies that provide enantioselective routes to substituted piperi dines, but also includes some specific target syntheses that illustrat e the power of the methods that have been developed, The three approac hes that have been most successful are: the use of the chiral pool, es pecially amino acids; the use of reagents that utilise a chiral cataly st; and the use of chiral auxiliaries in the asymmetric formation or d erivatisation of the piperidine ring.