Degradation of (—)-laudanosine, a 1-benzyl-1,2,3,4-tetrahydroisoquinoline alkaloid, with ethyl chloroformate (ECF) afforded
an optically active chloro-carbamate as an intermediate. The reason why this intermediate exhibits an optical
activity was investigated by comparison with the reactions of some model compounds with ECF. It may be supposed
that the chloride group in a hypothetic carbenium ion intermediate stands very closely to the chiral center, so conserving
optical activity. However, a neighboring group effect can not be excluded.