Oxa-7-aza-twistanes

As already mentioned in 2.2.7. only traces of the twistane 203 were obtained by olefin amination with mercuric acetate in dimethyl sulfoxide of the bicyclic amine 201. The main product was the corresponding 2-aza-7-oxa-isotwistane 202. 

Both bicyclic amines 227 and 228 with an exo-bromine atom at C(6) as the leaving group could be cyclized almost quantitatively in 1,2-dichloroethane in the presence 

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