New castor oil derived monomers via Baylis Hillman reactions

The Baylis-Hillman reaction is an organocatalytic and environmentally friendly reaction, in which an activated alkene is coupled with an aldehyde.[1,2] The sequence of Baylis-Hillman reaction and elimination of the hydroxy group leads to 1,3-dienes, which undergo diastereoselective Diels-Alder reactions.[3]
The reaction of methyl acrylate 1 with heptaldehyde 2 thus leds to the α,β﷓unsaturated hydroxycarboxylic acid derivative 3 in a good yield. 3 is a potential monomer for polycondensation reactions and radical polymerizations. The following one pot reaction sequence of mesylation, elimination and Diels-Alder reaction yields cyclohexene derivative 4 with a satisfying diastereoselectivity and good yield. Also 4 is an interesting candidate for polycondensations.

References
[1] A. B. Baylis, M. E. D. Hillman, German Patent 2155113, 1972.
[2] K.-S. Park, J. Kim, H. Choo, Y. Chong, Synlett 2007, 395.
[3] H. M. R. Hoffmann, U. Eggert, W. Poly, Angew. Chem. 1987, 99, 1047.