Question

Organocuprates predominantly react to give 1,4 -addition products with \(\alpha, \beta\)-unsaturated carbonyl species, while Grignard reagents often add to the carbonyl, in a process referred to as 1,2 -addition. To increase the yield of 1,4 -addition products, CuI is added to convert an easily prepared Grignard reagent into a organocuprate reagent in situ (during the reaction). Predict the major product and stereochemistry of the following reaction, assuming that the more stable chair product predominates.

Short answer

In the given reaction, identify the Grignard reagent and the α, β-unsaturated carbonyl species to predict the major product and its stereochemistry when the Grignard reagent is converted into an organocuprate reagent with CuI and undergoes a 1,4-addition.

Step-by-step solution

Identify the Grignard reagent and α, β-unsaturated carbonyl species

In this step, we need to locate the Grignard reagent and the α, β-unsaturated carbonyl species in the given reaction.

Convert the Grignard reagent into an organocuprate reagent

To increase the yield of the 1,4-addition product, we will add CuI to the reaction to convert the easily prepared Grignard reagent into an organocuprate reagent in situ (during the reaction).

Predict the 1,4-addition product of the reaction

Now that we have formed the organocuprate reagent, we can predict the 1,4-addition product of the reaction between the organocuprate and the α, β-unsaturated carbonyl species.

Determine the stereochemistry of the major product

The stereochemistry of the major product will be determined based on the more stable chair conformation. With this information, we can predict the stereochemistry of the major 1,4-addition product in the reaction between the organocuprate reagent and the α, β-unsaturated carbonyl species.