Question 1

Which of the following statements best describes the polarity of the carbon-metal bond in organolithium and Grignard reagents?

Accepted Answer

The carbon atom is partially negative and the metal is partially positive.

Question 2

Which of the following alkyl halides would react fastest with lithium metal to form an organolithium compound?

Accepted Answer

1-Iodopropane

Question 3

What is the product of the following reaction? $$\mathrm{CH_3CH_2MgBr + HC \equiv CH \rightarrow}$$

Accepted Answer

$$\mathrm{CH_3CH_3 + HC \equiv CMgBr}$$

Question 4

Which of the following best explains why Grignard reagents must be prepared and used under anhydrous conditions?

Accepted Answer

They are strong bases and react rapidly with water to form hydrocarbons.

Question 5

In the reaction of a Grignard reagent with a ketone followed by acid workup, what is the major product?

Accepted Answer

A tertiary alcohol

Question 6

Which of the following is the correct mechanism for the formation of methylmagnesium chloride from methyl chloride and magnesium?

Accepted Answer

Single electron transfer from Mg to CH$$_3Cl$$, forming a radical anion, followed by loss of Cl$$^-$$ and combination with Mg$$^+.$$

Question 7

Which of the following statements about the Simmons-Smith reaction is correct?

Accepted Answer

It converts alkenes to cyclopropanes using iodomethylzinc iodide.

Question 8

Which of the following organometallic reagents would be the best choice to synthesize 2-phenyl-2-butanol from acetophenone?

Accepted Answer

Ethylmagnesium bromide

Question 9

Which of the following statements about organocuprate (Gilman) reagents is FALSE?

Accepted Answer

They are more reactive than Grignard reagents toward carbonyl compounds.

Question 10

Which of the following best describes the electron count for a stable transition metal organometallic complex according to the 18-electron rule?

Accepted Answer

The metal center plus all ligands should sum to 18 valence electrons.

Question 11

Which of the following is a correct retrosynthetic disconnection for the synthesis of a tertiary alcohol using a Grignard reagent?

Accepted Answer

Disconnect at the C–O bond to give a ketone and an organomagnesium halide.

Question 12

Which of the following is the correct order of reactivity of alkyl halides with organocuprate reagents?

Accepted Answer

$$\mathrm{RI \u003e RBr \u003e RCl \u003e\u003e RF}$$

Question 13

Which of the following ligands is considered a strong field ligand in transition metal organometallic chemistry?

Accepted Answer

$$\mathrm{CO}$$

Question 14

What is the product of the reaction between phenylmagnesium bromide and 2-butanone followed by acid workup?

Accepted Answer

2-Phenyl-2-butanol

Question 15

Which of the following best explains why organometallic reagents are strong nucleophiles?

Accepted Answer

The carbon atom bonded to the metal is electron-rich due to the polarity of the C–M bond.

Question 16

Which of the following is a correct statement about the reaction of a terminal alkyne with a Grignard reagent?

Accepted Answer

The terminal alkyne acts as a stronger acid and is deprotonated by the Grignard reagent.

Question 17

Which of the following is the correct product of the reaction between lithium dimethylcuprate and 1-iododecane?

Accepted Answer

Undecane

Question 18

Which of the following best describes the mechanism of the Gilman coupling reaction?

Accepted Answer

Oxidative addition of the alkyl halide to the copper center, followed by reductive elimination to form the coupled product.

Question 19

Which of the following is a correct application of retrosynthetic analysis using organometallic reagents?

Accepted Answer

Disconnection of a tertiary alcohol to a ketone and a Grignard reagent.

Organometallic Reagents in Organic Chemistry: Structure, Preparation, and Reactivity

Guida di studio - Domande di pratica