An improved non-oxidative photochemical synthesis of aporphine derivatives has been developed, in which o-halobenzylidenetetrahydroisoquinolines are irradiated in the presence of potassium t-butoxide. The yield (72%) of one such product, N- carbethoxynorneolitsine (25) is the highest ever reported for any cyclization producing the aporphine ring system. Compound 25 was converted in two steps to cassameridine (4), ...
