New methodologies for the synthesis of highly functionalized carbocycles and heterocycles

The main topic of this thesis is the development of new methodologies for the synthesis of highly functionalized carbo- and heterocycles. The first part (chapter 2) describes an organocatalytic enantioselective synthesis of α-(benzylamino)cyclobutanones. Such products have been achieved by employing a tandem condensation/intramolecular rearrangement/proton transfer reaction and starting from racemic α-hydroxycyclobutanone and a selection of benzylamines. This reaction sequence afforded the products in good to high yields with moderate to high enantioselectivities. In the second part (chapter 3), a simple and practical protocol for the construction of synthetically important quaternary α-benzyl- and α-allyl-α-methylamino cyclobutanones in good to high yield, via a sequential one pot methylation/Stevens rearrangement, is reported. Finally, in the third part (chapter 4), a two-step protocol is presented for the preparation of 5-(pyridine-2-ylamino)dihydrofuran-2(3H)-ones from 2-hydroxycyclobutanone and some 2-aminopyridines via a catalyst-free synthesis of 2,2-bis(pyridine-2-ylamino)cyclobutanols followed by Dess-Martin periodinane mediated ring expansion.