Stereochemistry of product in Grignard-Gilman addition reaction

I would like to know whether the stereochemistry given in the following reaction is correct or not?



Which attack is more likely? axial or equatorial?





[Edited on 20-11-2017 by adianadiadi1]

Cyclohexene derivatives are not in a true chair conformation, hence there is no such thing as an axial/equatorial attack. Cyclohexene derivatives usually have two energetically favorable half-chair conformations the ³H₄ and the ⁴H₃. Since the drawn cyclohexene derivative is unsubstituted both states will be populated to an equal extent. Attack on these half-chairs can only occur from the bottom because the top-side would result in a twist boat conformation which is energetically unfavorable.
Based on this I would conclude there is no preference for one enantiomer, as both states are populated to an equal extent.

When compounds are drawn as a single diastereomer the enantiomer of said diastereomer is taken to be formed to an equal extent. (Most correct would be using the ± sign along with the drawing of the single diastereomer but this is often omitted). Now then onto the question which of the diastereomer is formed?
This is determined by on which face the enolate gets protonated in the acidic work-up. Since a proton is small I suspect there is no difference between the axial and the equatorial attack and result in an equal mixture of both enantiomers at the alpha position, i.e. a racemic mixture.

Protonation, depending on conditions can be reversible. If this is so the reaction will be under thermodynamic control and I suspect the equatorial-equatorial product will be the dominant one. This is not the product you've drawn.

A more simple way of looking at this is: Is chirality induced by the substate? No. Is it induced by the use of chiral reagents? No. Does magic happen? No. Thus the result will be a racemic mixture.



[Edited on 20-11-2017 by Sigmatropic]

[Edited on 20-11-2017 by Sigmatropic]



[Edited on 20-11-2017 by Sigmatropic]

Quote: Originally posted by Sigmatropic

Cyclohexene derivatives are not in a true chair conformation, hence there is no such thing as an axial/equatorial attack. Cyclohexene derivatives usually have two energetically favorable half-chair conformations the 3H4 and the 4H3. Since the drawn cyclohexene derivative is unsubstituted both states will be populated to an equal extent. Attack on these half-chairs can only occur from the bottom because the top-side would result in a twist boat conformation which is energetically unfavorable.