Preparation of Lithium Triorganozincates

Immobilized zincates such as 177 can be prepared by treating serine-bound 4-iodobenzoate with t-BujZnLi at 0°C. They react readily with aldehydes. Transme-tallation with lithium (2-thienyl)cyanocuprate provides the copper species 178 that undergoes 1,4-additions. Lithium trialkylzincates can be used for the preparation of benzylic zinc reagents using a very elegant approach of Harada. Thus, the treat- 

The high covalent degree of the carbon-zinc bond and the small polarity of this bond leads to a moderate reactivity of these organometallics towards many electrophiles. Only powerful electrophiles react in the absence of a catalyst. Thus, bromo-lysis or iodolysis reactions are high-yield reactions. In general, a direct reaction of 

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