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Please login to access the full content or check if you have access via3.4.3.2 Metal-Complex-Catalyzed Addition in C—N Bond Formation
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Mase, N., Science of Synthesis: Water in Organic Synthesis, (2012) 1, 195.
As noted in Section 3.4.3.1, in general a high temperature is required for aqueous conjugate addition of amine nucleophiles to electron-deficient alkenes in the absence of a catalyst. However, this reaction can be achieved at room temperature in the presence of a Lewis acid catalyst. Tin(IV) chloride (10 mol%),[109] ammonium cerium(IV) nitrate (CAN; 3 mol%),[110] polyaniline-supported indium(III) chloride (PANI-In; 10 mol%),[111] and 12-tungstophosphoric acid (H3PW12O40; 1 mol%)[112] have been found to be efficient catalysts for promoting conjugate addition reactions of amines 151 to electron-deficient alkenes 150 such as α,β-unsaturated esters, acrylamide, and acrylonitrile in water (Scheme 42). However, with respect to the scope of substrate and commercial availability, boron compounds are the recommended catalysts. Borax[113] and boric acid[114] efficiently catalyze the conjugate addition reaction of amines 151 to α,β-unsaturated aldehydes, ketones, esters, amides, and nitriles under aqueous conditions to afford the corresponding β-amino Michael adducts 152 in good yields at room temperature. The aqueous layer containing boric acid is reused for the next run. Borax and boric acid are efficient catalysts with aliphatic amine nucleophiles, but not with aromatic amines; on the other hand, 12-tungstophosphoric acid (H3PW12O40) is a suitable catalyst with aromatic amine nucleophiles.[112]
Meeeee 88 Meeeeeee ee Meeeee ee Meeeeeee-Meeeeeeee Meeeeee[888–888]
M8 | M8 | M8 | M8 | M8 | Meeeeeee (eee%) | Meee (e) | Meeee (%) | Mee |
---|---|---|---|---|---|---|---|---|
MM8Me | M | M | Me | M | MeMe8 (88) | 88 | 88 | [888] |
MM8Me | M | M | Me | M | MMM (8) | 8 | 88 | [888] |
MM8Me | M | M | Me | M | MMMM-Me (88) | 8.8 | 88 | [888] |
MM8Me | M | M | Me | M | M8MM88M88 (8) | 8.8 | 88 | [888] |
MM8Me | M | M | Me | M | M8MM88M88 (8) | 88 | 88 | [888] |
MM8Me | M | M | Me | M | eeeee (88) | 8 | 88 | [888] |
Me | M | M | (MM8)8 | M(MM)8 (88) | 8.8 | 88 | [888] | |
Me | M | M | Me | Me | M(MM)8 (88) | 8.8 | 88 | [888] |
MM8Me | M | M | Me | M | M(MM)8 (88) | 8.8 | 88 | [888] |
MM8Me | M | M | Me | Me | M(MM)8 (88) | 8.8 | 88 | [888] |
MM8Me | M | M | (MM8)8 | M(MM)8 (88) | 8.8 | 88 | [888] | |
MM8Me | Me | M | Me | M | M(MM)8 (88) | 8.8 | 88 | [888] |
MM8Me | M | Me | (MM8)8M(MM8)8 | M(MM)8 (88) | 8 | 88 | [888] | |
MMMM8 | M | M | Me | M | M(MM)8 (88) | 8 | 88 | [888] |
MM | M | M | Me | M | M(MM)8 (88) | 8.8 | 88 | [888] |
Meeeeeeeeeee Meeeeeeee
β-Meeee Meeeeeee Meeeeeeee ee Meeeeeeeee Meee Meeeeeeeeee 888; Meeeeee Meeeeeeee:[888]
Meeee eeee (8.888 e, 8.8 eeee) eee eeeeeeeee ee M8M (8 eM; eM 8.8) eeeeeeee ee eee eeeeeeee ee eee eeeee 888 (8 eeee) eee eee α,β-eeeeeeeeeee eeeeeeee 888 (8.8 eeee). Mee eeeeeee eee eeeeeee ee ee eee eee eeeeeeee ee eee eeeeeeee eee eeeeeeeee ee MMM. Meeee eeeeeeeeee ee eee eeeeeeee, eee eeeeeee eee eeeeeeeee eeee MeMMe (8 × 88 eM). Mee eeeeeeee eeeeeee eeeeeeee eeee eeeee (Me8MM8) eee eeeeeeeeeeee eeeee eeeeeee eeeeeeee, eee eee eeeeeeeee eeeeeee eee eeeeeeee ee eeeeee eeeeeeeeeeeeee [eeeeee eee, MeMMe/eeeeee (eeeee eeeeee eeee eeeeeee) ee, eee eeeeee, MeMMe/MeMM 8:8] ee eeeeee eee eeee β-eeeee eeeeee 888; eeeee: 88–88%. Mee eeeeeee eeeee eeeeeeeeee eeeee eeee eee eeeeee eee eee eeee eee.
References
[109] | Me, M.-M.; Me, M.; Mee, M.-M., Meee. Meee. Meee, (8888) 88, 8888. |
[110] | Meeeee, M.; Meeeeeeee, M.; Meeee, M. M., Meeeeee, (8888), 8888. |
[111] | Meeeee, M. M.; Mee, M.; Mee, M.; Meeeee, M. M.; Meeeeeee, M.; Meeeeeee, M. M.; Me, M. M., M. Mee. Meeee. M: Meee., (8888) 888, 888. |
[112] | Meee, M.; Mee, M.; Meeee, M.; Me, M.; Meeee, M., Meeeeeeee, (8888), 8888. |
[113] | Meeeeee, M.; Meeeeeeee, M. M.; Meeeeeeee, M. M.; Meeeee, M., Mee. M. Mee. Meee., (8888), 888. |
[114] | Meeeeeeee, M. M.; Meeeeee, M.; Meeeee, M. M.; Meeeeee, M., Meeeeeeeeee Meee., (8888) 88, 8888. |