F-BuOK

The intramolecular carbopalladation (or insertion) of the triple bond in dimethyl 4-pentynylmalonate (215) with Pd—H species and malonate anion as shown by 216 proceeds in the presence of f-BuOK and 18-crown ether, affording the methylenecyclopentane derivatives 217 and 218, the amounts of which depend on the reaction conditions. The Pd—H species may be formed... 

Ph3P)3RhCl allyl > 2-methyla Ilyl > but-2-enyl f-BuOK but-2-enyl > allyl > 2-methylallyl... 

A solution of 2,4-dichloro-2,.3-dihydro-1-benzothiepin (0.5 g, 2.16 mmol) in f-BuOH (14 mL) was added in one portion to a solution of f-BuOK (246 mg, 2.20 mmol) in t-BuOH (24 mL). After stirring for 50 min, the turbid orange solution was poured into H20 (150mL) and extracted with CHCl3. The extract was washed with H20 and dried (MgS04). The solvent was removed under reduced pressure to give a yellow oil [yield 330 mg (79%)] which was further purified by chromatography (alumina, petroleum ether). 

Equations 37 and 38 show a convenient procedure for the preparation of acetylenes and polyenes which utilizes an excess of f-BuOK as a base in THF or THF-f-BuOH. 

These reactions involve a diazonium ion (see 12-47) and are much faster than ordinary hydrolysis for benzamide the nitrous acid reaction took place 2.5 x lo times faster than ordinary hydrolysis. Another procedure for difficult cases involves treatment with aqueous sodium peroxide. In still another method, the amide is treated with water and f-BuOK at room temperature. " The strong base removes the proton from 107, thus preventing the reaction marked k j. A kinetic study has been done on the alkaline hydrolyses of A-trifluoroacetyl aniline derivatives. Amide hydrolysis can also be catalyzed by nucleophiles (see p. 427). 

This reaction to bicyclic compounds containing the aziridine group was also observed for other amides, viz., 44c-f, when treated with a catalytic amount of f-BuOK in THF or MeONa in methanol. LDA treatment of the tosyl-activated substrate 44 a gave the five-membered ring product albeit in a low yield (31 %). Remarkably, the carboxamide derived from the cz5-aziridine failed to react with base, probably due to steric hindrance. 

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