Aziridine aldehydes, dimerization

Amphoteric molecules, containing both nucleophilic and electrophihc nodes, were used in a domino aza-Michael/aldol reaction by the group of Yudin [30] (Scheme 7.3). In this process, an isolable aziridine aldehyde dimer 17 was used as a precursor, and the authors exploited the difference in dissociation kinetics... 

Researchers have found that the reduction of a variety of aziridine esters yields the corresponding aziridine aldehyde which dimerizes diastereoselectively <06JA14772>. The reduction of 112 with excess DIBAL yields the dimer 113, which is in equilibrium with the monomer 114. This molecule reacts as the monomer and both reduction to 115 or reductive amination to 117 proceed in quantitative yields. In a very interesting reaction, treatment of 113 with /V-benzyl tryptamine provides the pentacyclic 116 in excellent yield. 

Reversible dimerization of aziridine aldehydes has been found to control their dual-nucleophilic/electrophilic reactivity." ... 

Reaction with Further Electrophiles of Group IVA (Sl,Ge,Sn). IV-Silylated aziridines can be prepared from ethyleneimine by amination of chlorosilanes in the presence of an HC1 acceptor, by dehydrocondensation with an organosilicon hydride or by cleavage of a silicon—carbon bond in 2-furyl-, 2-thienyl-, benzyl-, or allylsilanes in the presence of an alkali metal catalyst (262—266). N-Silylated aziridines can react with carboxylic anhydrides to give acylated aziridines, eg, A/-acetylaziridine [460-07-1] in high yields (267). At high temperatures, A/-silylaziridines can be dimerized to piperazines (268). Aldehydes can be inserted... 

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