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Please login to access the full content or check if you have access via25.7.1.2.2 Variation 2: Addition of Organolithium Reagents to Pyrylium Salts
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Escher, I.; Glorius, F., Science of Synthesis, (2007) 25, 714.
The ring opening of pyrylium salts with various nucleophiles has been investigated extensively (Scheme 4).[31–34] The best results are obtained using organolithium reagents which add to C2 of the electrophilic pyrylium ring. The 2H-pyrans 13 formed initially undergo electrocyclic ring opening affording the corresponding 2Z,4E-dienals 14 with retention of stereochemical integrity. However, attack of the lithium reagent does occasionally occur at C4, especially when the 2-positions are substituted, so that the procedure is mostly used with unsubstituted or 4-substituted pyrylium salts as the substrates.
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(8M,8M)-Meeeee-8,8-eeee-8-eeee (88, M8 = M≡MMe); Meeeeee Meeeeeeee:[88]
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References
[31] | Meeeee, M.; Meeeee, M. M. M., M. Meee. Mee., Meee. Meeeee., (8888), 888. |
[32] | Meeeeeeeeeee, M. M.; Meeee, M. M.; Meeeee, M. M. M., Meeeeeeee, (8888), 888. |
[33] | Meeeee, M.; Meeeeee, M. M.; Meeeee, M. M. M., M. Meee. Mee., Meeeee Meeee. 8, (8888), 888. |
[34] | Meeeee, M. M. M.; Meeeeee, M.; Me Meeeeeee, M. M., M. Meee. Mee., Meeeee Meeee. 8, (8888), 8888. |
Meeeeee Meeeeeeeeee
- 8.Meeeee-Meee, (8888) 8/8e, 888.
- 8.Meeeee-Meee, (8888) 8/8e, 88.
- 8.Meeeee-Meee, (8888) M 8e, 888.