6a-Epipretazettine synthesis

Enzymatic oxidation 1216-1224 Enzyme-glutathione binary complexes 105 Epi-deoxyschizandrins, formation of 1278 6a-Epipretazettine, synthesis of 1244, 1248 Epoxidation, 

At this point the synthesis of the pretazettine nucleus with the inverted (cis) B-D ring fusion seemed possible starting from 11-epi-haemanthidine (262). Indeed, 262 easily undergoes rearrangement to N-demethyl-6a-epipretazettine (263) which cannot be converted back to the 5,10b-ethanophenanthridine form. Since 6a-epipretazettine 

The hypervalent iodine reagents PIFA and PIDA have also been used in the synthesis of naturally occurring structures, primarily the amaryllidaceae alkaloids and related species. Work by White s group showed the feasibility of this method for the synthesis of 6a-epipretazettine and (-)-codeine [45, 46]. In the early 1990s, Rama Krishna and co-workers demonstrated that PIDA can promote the oxidative phenolic coupling of diaryl substrates 38a-e to deliver cyclohexadienones 39a-e, respectively, in consistent 30 % yields for all of the substrates examined (Scheme 10) [47]. 

---