Study with the several resources on Docsity
Earn points by helping other students or get them with a premium plan
Prepare for your exams
Study with the several resources on Docsity
Earn points to download
Earn points by helping other students or get them with a premium plan
Community
Ask the community for help and clear up your study doubts
Discover the best universities in your country according to Docsity users
Free resources
Download our free guides on studying techniques, anxiety management strategies, and thesis advice from Docsity tutors
Benzyne Mechanism, Nucleophilic Aromatic Substitution for Hydrogen.
Typology: Lecture notes
1 / 15
This page cannot be seen from the preview
Don't miss anything!
Meisenheimer Complex Resonance Stabilized
SNAr Mechanism - addition / elimination
CF 3 , CN, CHO, COR, COOH, Br, Cl, I Common Activating Groups for NAS
LG Nu
LG Nu (^) Nu
LG
Resonance Stabilization of the Intermediate Anion[The Meisenheimer Complex]
Evidence for the Benzyne Mechanism
Trapping in Diels/Alder Reaction
Substituent Substituent Base No Reaction
Nu Nu
Isotopic Labeling
SN1 Mechanism
N N
slow
Nu Nu
Aryl Cation
N 2 RDS
Brown Chemistry Route to 4-ADPA
Cl (^2) c a t a l y s t
Cl HNO (^3)
Cl
NO (^2)
Cl
P N C B
E l e c t r o p h i l i c A r o ma t i c S u b s t i t u t i o n NO 2
Cl
NO 2
N (^) H
O C H
K 2 CO 3 N
H NO 2 KCl CO CO 2 4 - NDPA H 2 Catalyst
N
H NH 2 4 - ADPA
Nucleophilic Aromatic Substitution
PNCB
various organics
Atom Economy of the Traditional Chemistry
Cl 2
Cl HNO 3
Cl NO 2
Cl
30% 70% NO 2 N
H CO H N^ H NO 2 K^2 CO^3 H 2 N
H NH 2
1
(^2 )
(^54) 6
Reagent formula Reagent FW Utilized Atoms Wt Unutilized Atoms Wt 1 C 6 H 6 78 6C ,4H 53 2 H 2 2 Cl 2 70 ------------ 0 2 Cl 70 3 HNO 3 63 1 N 14 1 H, 3 O 49 4 C 7 H 7 NO 121 6 C, 6 H, 1 N 92 1 C, 1 O, 1 H 29 5 K 2 CO 3 98 ------------ 0 2 K, 1 C, 3 O 98 6 H 2 2 2 H 2 -------------- 0 TOTAL^432 12C ,12H, 2N^161 2C ,4H, 2C ,2K, 7O^248
H
NO 2
Nu: H^ Nu
N O O
H Nu
N O O
Nu
N O O
Nucleophilic Aromatic Substitution for Hydrogen
General Mechanism
Flexsys Route to 4-ADPA
Base-Promoted Coupling Reaction
Flexsys - Intermolecular Oxidation Pathway
Atom Economy of the Flexsys Chemistry
Reagent Formula Reagent FW Utilized Atoms^ Wt Unutilized Atoms Wt 1 C 6 H 6 78 6 C, 4 H 76 2 H 2 2 HNO 3 63 1 N 14 1 H, 3 O 49 3 C 6 H 7 N 93 6 C, 6 H, N 92 1 H 1 4 H 2 2 2 H 2 ----------- 0 TOTAL 236 12C, 12 h, 2 n 184 4H, 3O 52
