Enantiospecific Preparation of ((2R,6S)‐endo)‐5‐Aza‐1,10,10‐trimethyl‐ 3‐oxatricyclo(5.2.1.02,6)decan‐4‐one by a Nitrene‐Mediated Route from ( (1S)‐endo)‐(‐)‐Borneol and Its Utility as a Chiral Auxiliary in Some Asymmetric Transformations.

Abstract Attempted chiral aziridination of styrene by addition of optically-active alkoxycarbonylnitrene 5 derived from [(1 s )-endo]-(−)-bornyl-p-nitrobenzenesulphonoxycarbonate 4 is reported. No measurable asymmetric induction is observed under the various conditions employed, but in the absence of alkene, a tricyclic oxazolidin-2-one 8 is formed to which preparatively simpler access can be gained by thermal decomposition of azidoformate 7, either in 1,1,2,2-tetrachloroethane (50%) or by spray pyrolysis (58%). The oxazolidin-2-one 8 is demonstrated to be a successful chiral auxiliary by contemporary standards in a variety of asymmetric transformations, including alkylation, acylation, and aldol reactions for which high levels of asymmetric induction are observed. Diethylaluminium chloride-catalysed Diels-Alder reactions exhibit poorer selectivity except for the cinnamoyl derivative 23 which is stereospecific.