Imine metathesis polymerization

Scheme 8.1 Imine metathesis polymerizations of 1 and 2 in CH CN and CHCl and their reversible featnre [17,18],...

Figure 8.2 Schematic representation of the imine metathesis polymerization of 1 and 2 driven by folding of resnlting polymer 3 [17,18].

From time to time, synthetic transformations are reported that appear to be particularly convenient. One such is the procedure described by Paul Hanson of the University of Kansas (Tetrahedron Lett. 44 7187, 2003) for the conversion of an alcohol to the amine. The imine 2, easily prepared by the addition of maleimide to furan, couples under Mitsubobu conditions with the 1 to give the imide 3, contaminated with the usual impurities from the condensation. The crude imide 3 smoothly polymerizes under Ru metathesis conditions to give polymeric 3, from which the impurities are easily washed away. Exposure of the washed polymer to hydrazine then liberates the pure free amine 4. 

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