Juvabione synthesis D. A. Evans and J. V. Nelson

The sodium borohydride reduction in step C generates a mixture of diastereomers but this does not detract from the overall stereoselectivity beyond step A since this center is subsequently reoxidized. The fact that cyclization of this reduction product occurs is incidental to the overall strategy. 

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Juvabione synthesis J. Ficini, J. D Angelo, and J. Noire Juvabione synthesis D. A. Evans and J. V. Nelson Juvabione synthesis A. G. Schultz and J. P. Dittami Juvabione synthesis D. J. Morgans, Jr., and G. B. Feigelson Retrosynthesis of longifolene corresponding to the synthesis in Scheme 13.16... 

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