Hello everyone today we will discuss the reagent of Sodium hydride (NaH), Butyl Lithium (BuLi), and Alkyl halide (Like- Alkyl bromide) reaction with Ketone.
This question-Answer series is important for master of chemistry eligible entrance examinations like IIT JAM, DU, TIFR, etc. Corresponds to any national eligibility test like CSIR UGC NET, GATE, NTPC, etc.
The suggestive new pattern question in chemical science solution of organic chemistry. Approaching and conceptual question reagent without LDA (in the presence of one equivalent NaH, one equivalent BuLi).
Q.7. Major product X form Following the reaction: Predict the product X with the proper mechanism.
Answer: Reagents and Reaction mechanism Q.7
One of the very important reactions or organic syntheses in the production of natural products. The preparation of dianions using two equivalent of LDA (or one equivalent of sodium hydride followed by one equivalent butyllithium). And the formation of Beta-alkylated with high yield. This is the one type of Carbon-Carbon bond formation in the presence of organometallic reagents.
Formation of more reactive enolate which is a strong nucleophile.
Reaction mechanism Reagents NaH, BuLi, and Alkyl bromide:
- First of all Sodium hydride is act as a Base, which abstracts the proton from the alpha potion in the carbonyl compound. In presence of favorable solvent THF and HMPA that is protective and produced a good quality yield of enolate.
- Reaction part-2: Use of one equivalent butyl lithium replaced the enolate with lithium enolate. which is increase the nucleophilicity of enolate.
- Finally Nucleophile attack in the electrophilic center of alkyl halide. This reaction is a Nucleophilic substitute. we see that enolate act as a nucleophile and alkyl halide act as an electrophile. where substitute the Br-.
Reference
Modern organic synthesis by Carruthers Book. Chapter: Carbon-Carbon Singal Bond formation. In part of Organolithium catalysts or reagents react with a carbonyl compound: ketone, ester, aldehyde, etc.
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