Abstract:
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A stereoselective amination/cyclization cascade process has been developed that allows for the preparation
of a series of unsaturated and substituted caprolactam derivatives in good yields. This conceptually novel
protocol takes advantage of the easy access and modular character of vinyl g-lactones that can be
prepared from simple precursors. Activation of the lactone substrate in the presence of a suitable Pd
precursor and newly developed phosphoramidite ligand offers a stereocontrolled ring-opening/allylic
amination manifold under ambient conditions. The intermediate (E)-configured 3-amino acid can be
cyclized using a suitable dehydrating agent in an efficient one-pot, two-step sequence. This overall
highly chemo-, stereo- and regio-selective transformation streamlines the production of a wide variety
of modifiable and valuable caprolactam building blocks in an operationally attractive way. |