Bài giảng hóa hữu cơ phản ứng của arene

11.10 11.10 Reactions of Arenes: Reactions of Arenes: A Preview A Preview 1. Some reactions involve the ring. 1. Some reactions involve the ring. 2. In other reactions the ring is a substituent. 2. In other reactions the ring is a substituent. a) Reduction a) Reduction Catalytic hydrogenation (Section 11.4) Catalytic hydrogenation (Section 11.4) Birch reduction (Section 11.11) Birch reduction (Section 11.11) b) Electrophilic aromatic substitution b) Electrophilic aromatic substitution (Chapter 12) (Chapter 12) c) Nucleophilic aromatic substitution c) Nucleophilic aromatic substitution (Chapter 23) (Chapter 23) 1. Reactions involving the ring 1. Reactions involving the ring 2. The ring as a substituent (Sections 11.12 2. The ring as a substituent (Sections 11.12 - - 11.17) 11.17) catalytic catalytic hydrogenation hydrogenation (Section 11.4) (Section 11.4) Birch reduction Birch reduction (Section 11.11) (Section 11.11) H H H H H H H H H H H H H H H H H H H H H H H H H H H H Reduction of Benzene Rings Reduction of Benzene Rings H H H H H H H H H H H H H H H H H H H H H H H H 11.11 The Birch Reduction (80%) (80%) H H H H H H H H H H H H H H H H H H H H H H H H H H H H Na, NH Na, NH 3 3 CH CH 3 3 OH OH Birch Reduction of Benzene Birch Reduction of Benzene Product is non Product is non - - conjugated diene. conjugated diene. Reaction stops here. There is no further reduction. Reaction stops here. There is no further reduction. Reaction is not hydrogenation. H Reaction is not hydrogenation. H 22 is not involved in any way. is not involved in any way. H H H H H H H H H H H H Step 1: Electron transfer from sodium Step 1: Electron transfer from sodium + + Na Na• • + + Na Na + + Mechanism of the Birch Reduction (Figure 11.8) Mechanism of the Birch Reduction (Figure 11.8) H H H H H H H H H H H H • • •• •• – – Step 2: Proton transfer from methanol Step 2: Proton transfer from methanol Mechanism of the Birch Reduction (Figure 11.8) Mechanism of the Birch Reduction (Figure 11.8) H H H H H H H H H H H H – – • • •• •• OCH OCH 3 3 H H •• •• • • • • Step 2: Proton transfer from methanol Step 2: Proton transfer from methanol Mechanism of the Birch Reduction (Figure 11.8) Mechanism of the Birch Reduction (Figure 11.8) H H H H H H H H H H H H – – • • •• •• OCH OCH 3 3 H H •• •• • • • • H H H H H H H H H H H H H H • • OCH OCH 3 3 •• •• • • • • •• •• – – Step 3: Electron transfer from sodium Step 3: Electron transfer from sodium Mechanism of the Birch Reduction (Figure 11.8) Mechanism of the Birch Reduction (Figure 11.8) H H H H H H H H H H H H H H • • + + Na Na• • Step 3: Electron transfer from sodium Step 3: Electron transfer from sodium Mechanism of the Birch Reduction (Figure 11.8) Mechanism of the Birch Reduction (Figure 11.8) H H H H H H H H H H H H H H • • + + Na Na• • H H H H H H H H H H H H H H •• •• + + Na Na + + – – . 11.10 11.10 Reactions of Arenes: Reactions of Arenes: A Preview A Preview 1. Some reactions involve the ring. 1. Some reactions involve. ring 2. The ring as a substituent (Sections 11.12 2. The ring as a substituent (Sections 11.12 - - 11.17) 11.17) catalytic catalytic hydrogenation hydrogenation (Section 11.4) (Section 11.4) Birch. NH 3 3 CH CH 3 3 OH OH Birch Reduction of Benzene Birch Reduction of Benzene Product is non Product is non - - conjugated diene. conjugated diene. Reaction stops here. There is no further reduction. Reaction