Longifolene synthesis

The cyclization product was converted to an intermediate that was used in the longifolene synthesis described in Scheme 12.24. 

Scheme 13.20. Longifolene Synthesis E. J. Corey, R. B. Mitra, and P. A. Vatakencherry ...

Selectivity between secondary and tertiary alcohols by reagent Corey s longifolene synthesis Chemoselectivity in Enol and Enolate Formation... 

For example, in Corey s longifolene synthesis it was necessary to remove one ketone in the presence of another as shown below. Normally this would require protecting the ketone which is to remain. Both ketones are saturated, but they differ in steric environment. The total congestions calculated by SECS indicate that the ketone which is to remain is already protected by the... 

The third longifolene synthesis, disclosed by Volkmann, Andrews, and Johnson (23) and depicted in Chart 3, had its genesis in a chance observation. In continuation of their synthetic investigations on steroids... 

---