Morphinandienones rearrangement

The use of 2 -nitro or 2 -N-acetylamino substituents leads to cleavage at C-l. The trifluoroacetylation of amino group, however, changed the course of the reaction and the products were not morphinandienones but neospirodienones. This change of the reaction course may be initiated by rearrangement of the intermediate morphin-andienone-type cation. The addition of methanol to the reaction system as a nucleophile, however, makes it possible to trap the intermediate cation before its rearrangement. But the para-para coupling pattern is retained 10). 

The borane complex 75 when treated either with BF3OEt2 at room temperature followed by hydrogenation over Pt in methanol or with 1 N NaOH in methanol followed by reduction with sodium borohydride gave the tetrasubstituted dibenzazonine 76 in 75% yield (Scheme 20). This result supports the hypothesized intermediacy of JV-methylneospirinedienones in the acid-catalyzed rearrangement of morphinandienones to dibenzazonines, as in Scheme 16. On the other... 

A parallel reaction also leading to aporphines through the sequence morphinandienone-> neoproaporphineaporphine is the cone. HCl catalysed rearrangement of ( )-0-methylflavinantine (21) to l,2-dihydroxy-9,10-dimethoxyaporphine (22) in a remarkable 98% yield. Catechol 22 was then O-methylated to glaucine (20). Yet another example is the transformation of ( )-O-methylsalutaridine (23) to a mixture of corydine (24) and O-methylcorydine (25) (Scheme 3). ... 

Acid-catalysed rearrangement of the quinol ether (91), itself obtained by phenolic oxidative coupling, unexpectedly gave an aporphine which on O-methylation afforded 1,9,10-trimethoxyaporphine (92). Ferricyanide oxidation of reticuline supplied isoboldine and the morphinandienone pallidine. ... 

Since morphinandienones were postulated as intermediates in these transformations, it was only fitting that their acid-catalyzed rearrangement also be investigated. Indeed, it was established that they too lead to aporphines via neoproaporphines as shown below in the case of (9-methylflavinantine (18), the catalyst being concentrated hydrochloric acid. ... 

In view of Kupchan s in vitro synthesis of aporphines via the rearrangement of morphinandienones, it is rational to conceive of a Battersby-Kupchan... 

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