# Tag Info

7

The use of $\ce{NaI}$ in $\ce{MeCN}$ (a solvent in which $\ce{NaI}$ is quite soluble) is forming $\ce{Me3SiI}$ from the $\ce{Me3SiCl}$. The reason for doing this is $\ce{Me3SiI}$ is significantly more reactive with the triethylammonium enolate and will increase the yield of the TMS-enolate. You are correct in thinking that the white fume you see when adding ...

5

As I mentioned in my Comment the only serious issue was the formation of an allylic anion in acid medium. You seem to know how to form enols from ketones and how to form ketones from enols. I will ignore those steps in the diagram. Protonation of the carbonyl in 1 can cause ring fragmentation to form transient enol 2 that rapidly tautomerizes to diketone 3. ...

4

Enders SAMP/RAMP hydrazone chemistry will do this(1). The Wikipedia article on this technique is a good introduction: (1): Corey, E. J.; Enders, D. (1976). "Applications of N,N-dimethylhydrazones to synthesis. Use in efficient, positionally and stereochemically selective C-C bond formation; oxidative hydrolysis to carbonyl compounds". Tetrahedron Letters. ...

4

One problem with comparing product ratios using $\ce{LiN($i$Pr)2}$ vs $\ce{Ph3CLi}$ is that it's not really an apples-to-apples comparison - one is a lithium amide base, whereas the other is a alkyllithium that is highly stabilised by conjugation. I think this illustrates two important points: Things are more complicated than they first appear, ie. are the ...

4

Never say never! :-) Here is the answer for your question (Ref.1): Abstract: We report here that (1) enolate anions of five- to seven-membered cycloalkanones nucleophilically open cyclopentene and cyclohexene oxides in 57−76% yields and with 4−8:1 diastereoselectivity; (2) enolate anions formed regiospecifically via kinetic deprotonation of 2-...

2

I think you need a protection strategy and there are several choices. This one uses O'Donnell's benzophenone imine strategy details here. First you prepare glycine ethyl ester hydrochloride from glycine with EtOH/HCl, a method is here patent. From the ethyl ester hydrochloride prepare the benzophenone imine by O'Donnell's method as described in ref 1. This ...

1

As most of us chemists have understood and experienced, the Grignard reagent have undergone the many reactions with suitable substrates. Yet, the most familiar and probably the most used reaction is the addition to a carbonyl group to give $2^\circ$- or $3^\circ$-alcohol. The Grignard reagents' affinity for a corbonyl group in the presence of an acidic \$\...

1

As you will see if you look at the reference mentioned by @Mathew-Mahindaratne, the standard conditions for this transformation is NaH/KH in THF at reflux with diethyl carbonate (EtOCOOEt) with an acetic acid workup. The Organic Syntheses procedure here uses dimethyl carbonate, but will be equally applicable for diethyl carbonate.

1

I'll address your concerns about alkene stability in general and enamines in particular. It is useful to examine the acyclic permutations of C6H12. The heat of formation of these isomers is a good measure of their relative stability. As the double bond is increasingly substituted with alkyl groups, the heat of formation becomes more negative, i.e., more ...

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