2011年8月5日 · If NaNH 2 is a piranha, then today’s reagent – lithium diisopropylamide (LDA) is like a hammerhead shark. It’s also got a powerful bite, but that distinctive proboscis can get in the way.

Lithium diisopropylamide (commonly abbreviated LDA) is a chemical compound with the molecular formula LiN (CH (CH3)2)2. It is used as a strong base and has been widely utilized due to its good solubility in non-polar organic solvents and non-nucleophilic nature.

Because of its solubility in THF, LDA is a widely used base for enolate anion formation. In this application, one equivalent of diisopropylamine is produced along with the lithium enolate, but this normally does not interfere with the enolate reactions and is easily removed from the products by washing with aqueous acid.

In this Review, rate studies of LDA-mediated reactions are placed in the broader context of organic synthesis in three distinct segments. The first section provides a tutorial on solu-tion kinetics, emphasizing the characteristic rate behavior caused by dominant solvation and aggregation effects.

You can judge based on recovery of SM whether the anion requires more time to form or you need more LDA because adventitious water is present. If these two do not increase the yield then you may have an example where the electrophile has an acidic proton and it quenches the anion rather than forms a bond.]

A strong base, such as lithium diisopropyl amide (LDA), sodium hydride, or sodium amide, creates the nucleophilic enolate ion which reacts with an alkyl halide suitable for the S N 2 reactivity to …

To a mixture of the SM (5.5 g, 18.83 mmol) and tetramethylenediamine (2.95 mL, 18.83 mmol) in anhydrous THF was added dropwise LDA (1M in heptane, 38 mL, 37.67 mmol) at -20 C . . . …

2012年2月29日 · Lithium diisopropylamide is the chemical compound with the formula [ (CH3)2CH]2NLi. Generally abbreviated LDA, it is a strong base used in organic chemistry for the deprotonation of weakly acidic compounds. The reagent has been widely accepted because it is soluble in non-polar organic solvents and it is non-pyrophoric. LDA is a non ...

A very strong base, such as LDA, is often used because of its ability to form the enolate completely. Removal of the carbonyl starting material from the reaction mixture makes it unavailable for nucleophilic addition by the enolate.

2007年4月12日 · In this Review, rate studies of LDA-mediated reactions are placed in the broader context of organic synthesis in three distinct segments. The first section provides a tutorial on solution kinetics, emphasizing the characteristic rate behavior caused by dominant solvation and aggregation effects.