Bioactive Phytochemicals: Efficient Synthesis of Optically Active Substituted Flav-3-enes and Flav-3-en-3-o-R Derivatives

Scheme 3

Synthesis of flavenes. Reagents and conditions: (i) 12, LDA, THF, ice bath, 15%; (ii) 12, DBU, MeCN, reflux, 99%; (iii) 10, LDA, THF, ice bath, 5%; (iv) 10, DBU, MeCN, reflux, 82%; (v) 11, LDA, THF, ice bath, 44%; (vi) 11, DBU, MeCN, reflux, 80%.