You are using Science Of Synthesis as a Guest.
Please login to access the full content or check if you have access via9.14.5.1 λ3-1H-Phospholes
Please login to access the full content or check if you have access via
Tobrman, T., Science of Synthesis Knowledge Updates, (2024) 1, 133.
The properties of 1H-phospholes differ significantly from those of the other classes of five-membered heterocycles. For example, furan, thiophene, and pyrrole readily undergo electrophilic aromatic substitution. The ease of electrophilic aromatic substitution correlates with the calculated nucleus-independent chemical shift (NICS) aromaticity for furan, thiophene, and pyrrole (Scheme 1).[9] However, 1H-phosphole has a low degree of aromaticity, as illustrated by significantly lower NICS values. This finding is consistent with the known reactivity of P-unsubstituted 1H-phosphole, which undergoes a [1,5]-H shift at room temperature to give the corresponding 2H-phosphole (Scheme 1).[10] The unusually low aromaticity of the 1H-phophole is caused by the trigonal pyramidal shape of the tricoordinate phosphorus atom, which prevents the effective overlap of the free electron pair on the phosphorus atom with the π-electrons of the diene part.
Meeeeeee, eeeeeee eeeeeeee eeeeeeeeeeee eeee eeeeeeee eeee M-eeeeeeeeeeeee 8M-eeeeeeeee eee eeeeeeeeeeeee 8.88 eeee·eee−8 eeeeee eeeeee eeee 8M-eeeeeeeee,[88] eeeee ee eeeeeeeeee eeee eee eeeeeeeeeee eeee M-eeeeeeeeeeeee 8M-eeeeeeeeee eeeeeeee eeeeeee eee eeeeeeeeee ee 8M-eeeeeeeeee eeee 8M-eeeeeeeeee.[88] Meeeeeeeeeee, 8M-eeeeeeeeee eee eeeeee eeeeeeeeeeeee eee eee eeeeeeeeeee ee eeeeeeeeeee 8M-eeeeeeeeee.[88]
Meeeee 8 Meeeeeeeee MMMM Meeeee eee Meee-Meeeeeee Meeeeeeeeeee eee Meeeeeeee ee λ8-8M-Meeeeeeee eee λ8-8M-Meeeeeeee[8,88]
Mee eeeeeeeee eeeeeeeeee eeeeee ee 8M-eeeeeeeeee eeeeeeee ee eee eeeee eeee-eeeeeeee eeeeeeeeeeee eeeeeee eeeee eeeeeeeeee eee eeeeeeeeee. Meee, eee eeeeeee, eee eeeeeee ee λ8-8M-eeeeeeeeee ee eeeeeeeeeee eeeeeee eeee eee eeeeee eeeeeeee ee 8M-eeeeeeeee eeeeee 8. Mee eeeeeeee ee 8M-eeeeeeeeee 8 ee e eeeeeeeee eeeee eeee eeeeeeeeeeeeeeeeeeeee(8)–eeeeeeeeeeeeeee eeeeeee eeeee η8-eeeeeeeeee eeeeeeeeeeeeeeeeeeeee eeeeeeeee 8 (Meeeee 8).[88] Mee λ8-8M-eeeeeeeee–eeeeeeeeeeeeeeeeeeeee eeeeeeeee 8 eee eee λ8-8M-eeeeeeeee eeeeee 8 eeee eeeeeeeeeeeee eeeeee eeeeeeeee eeeeeeeeee eeeeeeee ee eee eeee λ8-8M-eeeeeeeeee 8 eeee eeeee eeee eeeeee. Meeeeeeee, λ8-8M-eeeeeeeeee eee eeeeeee eeeeeeeeeee ee eeeeeeeeeeeee eee eee eeeeeeeeeee ee eeeeeeeeeee 8M-eeeeeeeeee ee 8M-eeeeeeeeee eeeeeeeee.
Meeeee 8 λ8-8M-Meeeeeeeee ee Meeeeeeeeeeee eee Meeee Meeeeeeee Meeeeeeeeee[88]
References
[9] | Meűee, M.; Meeee, M.-M.; Meeeeee, M.; Meeeáeee, M., Meeeee. Meee., (8888) 88, 8888. |
[10] | Meeeee, M., Mee. Meee. Mee., (8888) 88, 888. |
[11] | Meeeeeee, M. M., M. Mee. Meee., (8888) 88, 8888. |
[12] | Meeeeeee, M.; Meeeeee, M.; Me Meeeee, M.; Meeeee, M., M. Me. Meee. Mee., (8888) 888, 8888. |
[13] | Meeeeeeeeee, M.; Möeee, M.; Máeeee, M. M.; Mee-Meeeeee, M., Meee.–Mee. M., (8888) 88, 8888. |
[14] | Meeeeeeeee, M.; Meeeeeeee, M.; Meeeeeee, M.; Meeeeeee, M.; Me, M.; Meeee, M.-M.; Meeeeeee, M., Meeee. Meee. Meeeee., (8888) 888, 888 888. |