| The Morita-Baylis-Hillman (MBH) reaction, currently at the forefront of chemical research, has become a well-known, atom economical method of carbon-carbon bond formation, allowing for the synthesis of highly functionalized products. This thesis reports a novel extension of the aza-version of the MBH reaction, employing for the first time activated diene systems as substrates.; Reactions of various N-(benzylidene)-benzenesulfonamides were carried out with 1-(p-toluenesulfonyl)-1,3-butadiene in the presence of 3-hydroxyquinuclidine as a catalyst. Reactions were generally successful, yielding E/Z mixtures of the desired MBH adducts, in fair to good yields, under mild reaction conditions. The E-isomers of the MBH adducts, possessing both an amine functionality and an activated diene moiety, were then made to undergo an intramolecular conjugate addition reaction under basic conditions to afford substituted piperidines. The Z-adducts were unable to cyclize due to geometric constraints; however, equilibration of E- and Z-isomers was effected by irradiation at 300 nm. Thus, cyclizations carried out in the presence of 300nm light provided improved yields of the products.; This newly developed methodology was also applied to MBH reactions employing methyl 2,4-pentadienoate, as opposed to the p-toluenesulfonyl activated diene described above. These reactions also provided the desired MBH adducts in reasonable yields, again as mixtures of E- and Z-isomers. As before, the E-adducts could be cyclized to afford the analogous methyl ester-substituted piperidines, while the Z-isomers did not react.; Also described in this thesis are investigations into subsequent transformations possible for either the sulfone-substituted MBH adducts or the piperidines obtained from the latter, including a successful Heck reaction to generate a bicyclic system, as well as synthetic steps towards the natural product (+/-)-anabasine. |
