Dimethylzinc

Chemical Properties

Clear colorless liquid

Uses

Activator for radical trifluoromethylation of silyl enol ethers leading to α-trifluoromethyl ketones.1

Uses

Dimethylzinc is pharmaceutical compound comprising Hemiasterlin derivatives and its antibody conjugate for treatment of cancer.

Uses

Dimethylzinc solution can be used as:

• A catalyst with nickel for the stereoselective C2 alkenylation and dialkenylation of pyridine derivatives by alkynes to give monoalkenylation products.
• A reagent with aldehydes and 2-methoxyaniline for the synthesis of enantioselective alkyl and aralkyl secondary amines via one-pot three-component coupling reaction in the presence of zirconium tetraisopropoxide.
• A methylating reagent for methylation of fluoroalkylated pyruvates in the presence of copper/chiral diphosphine catalyst.

Definition

ChEBI: Dimethylzinc is a dialkylzinc compound.

General Description

Mobile liquid, with peculiar garlic odor.

Air & Water Reactions

Highly flammable. Ignites in air and burns with a blue flame giving off a peculiar garlicky odor. Explodes in oxygen or ozone. Reacts violently with water to generate methane [Merck, 11th ed., 1989; Brauer(1965)]. Very slow oxidation with traces of air to give methylzinc methylate.

Reactivity Profile

DIMETHYLZINC is very reactive, acts as a strong reducing agent. Combines with acids, with alcohols (methanol, ethanol), and 2-2-dichloropropane as well as with water with explosive violence. When heated to decomposition emits toxic fumes of zinc oxide [Bretherick, 5th ed., 1995, p. 354]. Oxidants may yield peroxide formation, which is explosive.

Health Hazard

Inhalation of mist or vapor causes immediate irritation of upper respiratory tract. Excessive or prolonged inhalation of fumes from ignition or decomposition may cause ``metal fume fever'' (sore throat, headache, fever, chills, nausea, vomiting, muscular aches, perspiration, constricting sensation in lungs, weakness, sometimes prostration). Symptoms usually last 12-24 hrs. Eyes are immediately and severely irritated by liquid, vapor, or dilute solutions. If not removed by thorough flushing with water, chemical may permanently damage cornea. Skin will undergo thermal and acid burns when chemical reacts with moisture in skin. Unless washed quickly, skin may be scarred. Treat dilute solutions with same precautions as concentrated liquid. Ingestion, while unlikely, would cause immediate burns at site of contact. Nausea, vomiting, cramps, and diarrhea may follow. Tissues may ulcerate if not treated.

Synthesis

A method for the preparation of dimethyl zinc, comprising the following steps: adding zinc fluoride to a reaction kettle under the protection of nitrogen, then adding trimethylaluminum dropwise under stirring conditions, the molar ratio of trimethylaluminum and zinc fluoride is 1:2, and the reaction rate is controlled by the dropwise acceleration of trimethylaluminum, and after the completion of the dropwise addition of trimethylaluminum, the reaction is continued with stirring for 4 hours, and then the temperature of the kettle is adjusted to 75C and maintained for 2.5h, and collecting the Zn(CH₃)₂ was evaporated; then diethylzinc was added dropwise to the reaction kettle, and the molar ratio of trimethylaluminum and diethylzinc was 1.2:1, and the kettle temperature of the reaction kettle was controlled to be 100 , and the evaporated Zn(CH₃)₂ was collected, and after completion of the addition of diethylzinc, the reaction speed was controlled by the dropping acceleration of trimethylaluminum. kettle temperature of 100C for 2 hours to continue collecting Zn(CH₃)₂. The yield of dimethylzinc in this method is 95% (calculated as the methyl of trimethylaluminum).