2‐(p‐Tolylsulfinyl)benzyl Halides as Efficient Precursors of Optically Pure trans‐2,3‐Disubstituted Aziridines

Abstract

Aziridination of (R)-N-sulfinylaldimines (aryl, heteroaryl and alkenyl derivatives) with 2-(p-tolyl sulfinyl)benzyl iodide in the presence of sodium hexamethyl disilazide takes place with almost complete control of the stereoselectivity (facial and anti/syn) and with very high yields affording optically pure N-sulfinyl trans-2,3-disubstituted aziridines 7. Simultaneous removal of both C- and N-p-tolylsulfinyl groups with tBuLi provides the corresponding trans-NH aziridines 8 without affecting their optical purity. Some experimental results suggest these processes evolve through benzyl halocarbenoids as intermediates, whereas theoretical calculations support the formation of benzyl carbanions. These results have served for revising the mechanistic aspects of the reactions of substituted 2-p-tolylsulfinyl benzylcarbanions with electrophiles.