Asymmetric synthesis Nazarov cyclization

A similar type of chiraUty transfer was exploited by Tius in the total synthesis of roseophilin (69) (Scheme 3.15) [18]. A key intermediate in the synthetic pathway consisted of a substituted cyclopentanone, constructed via a Nazarov-type cyclization. The asymmetric cyclopentannulation reaction was initiated by generating the cyclopentenyl intermediate in situ using the lithioallene 64 and the amide 65. The chiral substituent on the delocahzed carbocation 66 induced... 

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