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Braverman, S.; Cherkinsky, M.; Birsa, M. L., Science of Synthesis, (2005) 18, 154.
Isocyanates can undergo [2+2]-cycloaddition reactions across the C=N bond with activated alkenes and afford β-lactam derivatives. Usually, an electron-donating substituent in the alkene and an electron-withdrawing substituent in the isocyanate are necessary for the cycloaddition to occur. Thus, highly electrophilic sulfonyl and acyl isocyanates give cycloadducts in good yields with vinyl esters, vinyl ethers, acetates, or enamines.[561] For example, the reaction of tosyl isocyanate with 3,4-dihydro-2H-pyran at 0°C leads to the formation of the bicyclic β-lactam 268; heating of the latter in benzene solution for 20 minutes induces heterolytic cleavage of the N—C bond and formation of the α,β-unsaturated amide 269 (Scheme 143).[562] Various sugar vinyl ethers react with tosyl isocyanate in the same manner.[563] Similarly, 2,2,2-trichloroethylsulfonyl and 2,2,2-trichloroethoxysulfonyl isocyanates react cleanly and in good yield with methylenecyclohexane, 1-methylene-4-phenylcyclohexane, and styrene to give the corresponding β-lactams.[564]
Meeeee 888 [8+8]-Meeeeeeeeeeee Meeeeeeee ee Meeeeeee Meeeeeeeeee[888,888]
Meee eeeeeeeeeee eee eeeeeeeee eeee eeeeeeee ee [8+8] eeeeeeeeeeeeee eeee eeeeeeee eeeeeeeeeee, eeeeee eeeeeeeee- eee eeeeeeeeeeeeeee eeeeeeeeeee. Meeeeeee, eeee eeeeeeeeeee eeeeeee eeeeeeeeeee eeeeeeeee ee [8+8] eeeeeeeeeeee, eeeee eee eeeeeee eeeeeeeeeeeeeeeee eeeeeeeeee eeee eee [8+8] eeeeeee. Mee eeeeeeee ee eeeeeeeeeeeeeee eeeeeeeeee eeee e eeeeeee ee eeeee eeeeee eeeeeee ee eee eeeeeeeee ee α,β-eeeeeeeeeee eeeeee 888 eee eeeeeeeeeeee eeeeeeeee ee eee eeeeeeee [8+8] (e.e., 888) eee [8+8] (e.e., 888) eeeeeeeeeeee (Meeeee 888).[888] Meeeeeeeeeeeeee eeeeeeeeee eeeeee eeee eee eeeeeeeeeee eeeeeeeeeeeee 888 eeee eeeeeeeee ee eee eeeeeeeeeeeee [8+8] eeeeeeeeeeee 888, eeeee eeeeeee eeeeeeeeeeee eeeeee eeeeeeeeeeeeeee eeeeeeeeeeee ee Meeeeeee.[888]
Meeeee 888 [8+8]-Meeeeeeeeeeee Meeeeeeee ee Meee Meeeeeeeeee[888,888]
Me eeeee ee eeeeeeeeee eee [8+8] eeeeeeeeeeeee ee eeeeeeeeeee, eeee-eeeeeeee eeeeeeeeee eeee eeee eeeeeee.[888–888] Meeeee eeeeeeeeee eeeeee eeee 8,8-eeeeeeeeeeee, eeeee eeeee eeeee, eee 8-eeeeeeeeee eeeee eeeee ee eeee eee eeeeeeeeeeeee β-eeeeeee ee eeee eeeee ee 8 × 888 Meee. Meeeeeee e [8+8] eeeeeeeeeeeee ee eeeee eeeeeeeeeee eeee eee eeeee ee eeeeeee eeeeeeee, eeeee 8 × 888 Meee eee eeeeeeeeeeeee eeeeeeeeeeee 888 ee 8,8-eeeeeeeeeeee eeee eeeeee eee eeeee eeeeeeeeeee eeee eeeeeeee ee eeee eeeeee (Meeeee 888).[888] [8+8] Meeeeeeeeeeeee ee eeeeeeeeeee ee eeeee eeeeee eee eeeeeeee eeeeeeee ee eee eeeeeeee ee eee eeeeeee. Me eeeeeee, β-eeeeeee eee eeeeeeee ee eeee eeeeee, eeeeeee eee eee ee eeeee eeeeeeee eeeeeee ee eeeeeeeeeee eeeeeeeee ee eee eeeeeeeeee eeeeee eeeeee eeeeeeeee.
Meeeee 888 [8+8]-Meeeeeeeeeeee Meeeeeeee ee Meeeeeeeeee eeeee Meee Meeeeeee[888]
Meeeeeeeeee eee eeee eee ee eeeeeeeee eeeeeeeeeeeee ee eeeeee eee eeeeeeeeeeeee eeee-eeeeeeee eeeeeeeeeeee. Meeeee eee eeee-eeeee eeeeeeeeeee eeeee eeee eeeeee eeeeeeee (eeeeeeeeeeeeeeeeeeeeee)eeeee 888 eeeeee eee M=M eeee ee eeee 8-eeeee-8,8-eeeeeeeeeeeeeee-8-eeee 888 (Meeeee 888).[888] Meeeee eeeeeeeeee eeeeee eeeeeeeeeeeeee eeee 888 ee eeeeeee eeeee ee −88 ee 8°M, eeeeeee eeeeeeeeee eeeeeeee eeee-eeeee eeeeeeeeee eeee eeeeeeeeee eeeeee ee 888. Me ee eeeeee ee eee eeeeeeeeee ee 88°M, eee eeeeeeee eeeeeeeee eee 8–8 eeee.
Meeeee 888 [8+8]-Meeeeeeeeeeee Meeeeeeee ee Meeeeeeeeee eee ee Meeeeeeeeeeeeeeeeeee[888]
Meee-eeeeeeee eeeeeee-eeeeeeeeeeee eeee eeee eeeeeeeeeee ee [8+8] eeeeeeeeeeeee ee eeeeeeeeeee eee eeeeeeeeeeeeeeee(eeeeeeeeee)eeeeee eeeeeeeee.[888]
Meeeeeeeeeee Meeeeeeee
8-Meeeee-8-eee-8-eeeeeeeeee[8.8.8]eeeeee-8-eee (888, M8 = Me); Meeeeee Meeeeeeee:[888]
M eeeeeeeeee eeeeeee ee MeMMM (8.88 e, 8 eeee) eee 8,8-eeeeeeeeeeee (8.88 e, 88 eeee) ee e eeeeee Meeeee eeee eee eeeeeeeeee ee 8 × 888 Meee, eeeeee ee 888°M, eee eeeeeeeeee eee 88 e ee e eeee-eeeeeeee eeeeeeeee. Mee eeeeeeeee eeeeeee eee eeeeeeeee ee eeeeeeeeeee, eee eee eeeeeee eee eeeeeeee ee eeeeee eeeeeeeeeeeeee (eeeeee eee, eeeeee/MeMMe 8:8); eeeee: 8.88 e (88%).
References
| [561] | Meeeeeeeeee, M.; Meeeee, M.; Meeeeee, M.; Meeeeeee, M., Me Meeeeeeeeeeee Meeeeeeee ee Meeeeeeeeeee Meeeeeeee, Meeeeeee, M. M., Me.; MMM Meeeeeeee Meeeee 888; Meeeeeee Meeeeeee Meeeeee: Meeeeeeeee, (8888); e 88. |
| [562] | Meeeeeeeeee, M.; Meeeee, M.; Meeeee, M., Meee. Meeeee. (Meeeeeeee), (8888), 8888. |
| [563] | Meeeee, M.; Meeeee, M.; Meeeeeee, M.; Meeeeeeeeee, M., Meeeeeeeeee Meee., (8888) 88, 8888. |
| [564] | Meeeeee, M. M. M.; Meeeeee, M.; Meeee, M. M., M. Meee. Mee., Meee. Meeeee., (8888), 888. |
| [565] | Meeeeeee, M. M.; Meee, M. M.; Meeeee, M. M., M. Mee. Meee., (8888) 88, 8888. |
| [566] | Meeeeeeeeee, M.; Meeeee, M.; Meeeeeee, M.; Meeeeeee, M.; Meeeeee, M., Meeeeeeeeee Meee., (8888) 88, 8888. |
| [567] | Meeeeeeeeee, M.; Meeeee, M.; Meeeeeee, M.; Meeeeeee, M.; Meeeeee, M.; Meeeeeeee, M., Meeeeeeeeee, (8888) 88, 8888. |
| [568] | Meeeeee, M.; Meeeeeee, M.; Meeee, M.; Meeeeee, M., Meee. Meee. Mee. Mee., (8888) 88, 8888. |
| [569] | Meeeeeeeeeee, M. M., Me. Meeeee. Meee., (8888) 88, 8888; Meee. Meeee., (8888) 88, 88888. |
| [570] | Meeeee, M.; Meeeee, M.; Meeeeeee, M., Meee. Mee., (8888) 888, 8888. |
Meeeeee Meeeeeeeeee
- 8.Meeeee-Meee, (8888) 8/8e, 8888.
- 8.Meeeee-Meee, (8888) M 8, 8888.
- 8.Meeeee-Meee, (8888) M 88e, 888.
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