158x Filetype PPTX File size 0.36 MB Source: osf1.gmu.edu
Schedule of day: ■ PPE check – at the door ■ Pre-lab check – at the door ■ Quiz ■ Recitation – Synthesis of Dibenzalacetone ■ Safety – Put bags away – Goggles – Gloves – Lab Coat ■ LAB! Due Dates ■Today – Synthesis of Banana Oil Report due – End of lab – notebook copy pages (Synthesis of dibenzalacetone) ■Next Week – At the beginning of lab – Synthesis of Dibenzalacetone Report • See “Notebook & Report Formats” on Bb for instructions for a synthesis report. ■Two Weeks – Final Exam Synthesis of Dibenzalacetone ■ This reaction is an example of an aldol condensation. O C O O H NaOH 2 + CH C CH CH=CH C CH=CH 3 3 ■ The reaction is also a mixed aldol, between and aldehyde and a ketone. ■ The product is quite stable because of conjugation (resonance stabilization), and so product formation is highly favored. Synthesis of Dibenzalacetone ■Only the ketone has an alpha-H that can be - removed by OH base to form the enolate: O O O HO H CH C CH HO CH C CH CH C CH 2 3 2 2 3 2 3 ■ O O O O The carbonyl group in the aldehyde is more Ph C H CH C CH Ph C CH C CH 2 3 2 3 reactive than the carbonyl of the ketone: H Synthesis of Dibenzalacetone ■The tetrahedral intermediate from addition is protonated: H O O O O The tetrahedral intermediate from Ph C CH C CH HO Ph C CH C CH HO 2 3 2 2 3 addition is protonated: H H H O O O ■ Then dehydration occurs to give a stable conjugated Ph C CH C CH HO HO Ph C CH C CH HO 3 2 3 H product (a,b-unsaturated ketone): H H
no reviews yet
Please Login to review.