You are using Science Of Synthesis as a Guest.
Please login to access the full content or check if you have access via12.4.4.2.2 Of Metals
Please login to access the full content or check if you have access via
Grimmett, M. R., Science of Synthesis, (2002) 12, 588.
The most important reactions of this type synthetically are those that replace a lithium or Grignard reagent group by an electrophile.[342,343] Such metallic groups are readily replaced by reaction (quenching) with alkyl and acyl halides, aldehydes and ketones, carbon dioxide, chlorotrimethylsilane, halogen sources, and reagents such as dimethylformamide (introduces a formyl group), disulfides, and tosyl cyanide. The reactions have to be carried out with dry apparatus and solvents, and often require specialized techniques, which are detailed in Wakefield's monograph.[385] The lithiation process is outlined above (Section 12.4.4.2.1.2). Protected benzimidazoles [with hemiaminal,[345] (dialkylamino)methyl,[349] benzyl, sulfonyl, and other suitable groups in the 1-position] are lithiated, then quenched with an electrophile before acid-catalyzed deprotection. The reactions are largely used for making 2-substituted benzimidazoles 104 (Scheme 52). Examples of 2-substituted benzimidazoles made from 1-(dialkylamino)methyl-substituted 2-lithiobenzimidazoles include the 2-deutero (R2 = D, 87%), 2-methyl (R2 = Me, 69%), and 2-phenylcarbamoyl (R2 = CONHPh, 79%) derivatives.[349] Scheme 52 shows some examples of 2-substituted benzimidazoles 104 made from 1-(hydroxymethyl)-2-lithiobenzimidazoles 103.[345]
Meeeee 88 8-Meeeeeeeeee Meeeeeeeeeeeee eee 8-Meeeeeeeee ee Meeeeeeee Meeeeeeeee[888]
Meeeeeeeeeee | M8 | Meeee (%) ee 888 | Mee |
---|---|---|---|
MeMMM | MM(MM)Me | 88 | [888] |
8-MeM8M8MMM | MM(MM)M8M8-8-Me | 88 | [888] |
Me8MM | M(MM)Me8 | 88 | [888] |
eeeeeeeeeeeee | 8-eeeeeeeeeeeeeeeee | 88 | [888] |
Me8M8 | MMe | 88 | [888] |
Me8M8 | MMe | 88 | [888] |
Meeeeeeeeeee Meeeeeeee
8-Meeeeeeeeee 8M-Meeeeeeeeeeeee 888 eeee 8-Meeeee Meeeeeeeee; Meeeeee Meeeeeeee:[888]
8-(Meeeeeeeeeeee)-8-eeeeee-8M-eeeeeeeeeeeee (888) (eee Meeeeee 88.8.8.8.8.8) [eeee eeee 8-(eeeeeeeeeeeee)-8M-eeeeeeeeeeeee (88.8 eeee)] ee eee MMM/eeeeee eee eeeeeeee eeee ee eeeeeeee, eeeeee, ee eeeeeeeee (88.8–88.8 eeee) ee −88°M, eee eee eeeeeee eee eeeeeee ee eeeee eee 8 e ee eeee eeeeeeeeeee eeeeee eeeeee eeeeeee ee −88°M eeee 8 e. Mee eeeeeee eee eeeeeeeeeee ee eeeeeeeee ee 8°M eeee ee MM8Me (88 eM), eeeeeeee eeee Me8M (888 eM), eee eeeeeee eeeeeeeeee (8 ×) eeee 8 M MMe. Mee eeeeeee eeeeeeee eeee eeeeeeee, eeee eeeee eeee MM8 eee (MM8)8MM8 eeee eeeeeeee ee 8°M, eee eee eeeeeeeeeee eee eeeeeeee, eeeee (eeeee ee eee eeeeee eeee, eeee eeeee eeeeee eee 88 e), eeeeee eeee ee eeeeeeeeeee eeeeeee, eee eeeeeeeeeeeeee. Me eeeee eeeee ee eeeeeeeeeee eee eeeeeeee, eee eeeeeee eeeee eee eeeeeeeee eeee Me8M ee MeMMe eee eee eeeeeeee eeee eeeee eee eeeeeeeeee ee eeeee ee eeee e eeeee, eeeee eee eeeeeeeeeeeeee.
References
[342] | Meeeee, M. M.; Meeeeeeeeee, M. M., Meee. Meeeeeeeee. Meeee. (Meee. Meeeee.), (8888) 88, 888. |
[343] | Meeeeeeee, M.; Meeeeee, M.; Meeeeeee, M.; Meeeee, M.; Meeeee, M.; Meeeeee, M.; Meeeeeeee, M., Meeeeeeeeeee, (8888) 88, 888. |
[345] | Meeeeeeee, M. M.; Meeeeeeee, M., M. Mee. Meee., (8888) 88, 8888. |
[349] | Meeeeeeee, M. M.; Meeeeeeee, M. M.; Mee, M.-M., M. Mee. Meee., (8888) 88, 8888. |
[385] | Meeeeeeee, M. M., Meee Meeeeeeee Meeeeee: Meeeeeeeeeeee Meeeeee, Meeeeeee: Meeeee, (8888). |
Meeeeee Meeeeeeeeee
- 8.Meeeee-Meee, (8888) 8/8e, 888.
- 8.Meeeee-Meee, (8888) M 8e, 888.
- 8.Meeeee-Meee, (8888) M 8e, 888.
- 8.Meeeee-Meee, (8888) M 8e, 888.