23. What is the major organic product obtained from the following reaction? (A) 1 (B) 2 (C) 3 (D) 4 (E) 5

19. When a carbonyl is part of a conjugated π-network, the C=O stretch: (A) has a higher frequency than in a nonconjugated system. (B) has a lower frequency than in a nonconjugated system. (C) always occurs at 1710 cm-1 . (D) occurs around 2700 cm-1 . (E) cannot be distinguished from the C=O stretch in a nonconjugated system.