An original tandem reaction consisting of a thermal elimination–addition process was developed.

A solvent‐free organocatalyzed intermolecular cyclization reaction starting from β‐substituted γ‐hydroxy‐α,β‐unsaturated esters and aryl isothiocyanates proceeds via an aza‐Michael addition to provide previously unknown quaternary oxazolidine‐2‐thione β3‐amino ester analogs. A panel of diversely‐substituted esters was investigated, including β,γ‐disubstituted examples which provided the target molecules with very high cis diastereoselectivity.

We have developed one-step protocols for the preparation of a large selection of α-aminocyclopropyl ketones or benzo[d]imidazoles, by reacting 2-substituted-2-hydroxycyclobutanones with aryl amines or o-phenylenediamines, respectively. In most case the reactions proceed at room temperature and are catalyst-free. The formation of benzo[d]imidazoles is rationalized in terms of an unusual ring-closure/ring-fission process followed by aromatization.