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Download fileThermal and Catalyzed [3,3]-Phosphorimidate Rearrangements
journal contribution
posted on 11.05.2005, 00:00 authored by Bin Chen, Anna K. Mapp[3,3]-Sigmatropic rearrangements have been widely utilized for the synthesis of structurally
complex organic molecules because of the ease with which carbon−carbon bonds are formed in a regio-
and stereocontrolled manner. However, there are far fewer [3,3]-rearrangements available for the selective
formation of carbon−nitrogen bonds despite the enormous potential of such reactions for the preparation
of stereodefined allylic amines. We describe here the scope and mechanism of a [3,3]-rearrangement of
allylic phosphorimidates that provides access to stereodefined allylic amines of diverse structure. The reactive
intermediate in the reaction, an allylic phosphorimidate, is produced in situ through the combination of
readily available starting materials (allylic alcohols, chlorophosphites, and organic azides), rendering the
reaction an efficient three-component process. Analogous to other [3,3]-rearrangements, the stereochemistry
in an allylic alcohol starting material is transferred with fidelity to the allylic amine product and, further,
allylic amines are produced as single olefin isomers. In addition, a crossover experiment indicates that the
rearrangement is an intramolecular process. Finally, activation of the allylic moiety either through
incorporation of electron-deficient functional groups or through the use of a transition-metal catalyst
significantly facilitates the reaction and consequently the preparation of a wider range of substitution patterns.