Synthesis of Reformatsky Reagent in THF

A 250 ml round-bottomed flask, under Ar, was charged with 50 ml of Rieke Zn solution (5g at O.lg/ml 76mmol). The flask was cooled between 5 and 10°C using a water bath with a little ice. The tert-butyl chloroacetate was added dropwise over 10 min. The temperature was maintained between 5 and 20°C. After stirring for 2h, the reaction was determined to be complete by GC. The reaction was centrifuged to remove excess Rieke Zn, botded under Ar, and diluted to 100 ml with fresh THF (0.5 M). 

11 Configurationally Stable Organozinc Reagents and Intramolecular Insertion Reactions 

The active zinc may also lend itself toward the possibility of forming configurationally stable organometallics. For example, cM-4-tert-butylcyclohexyl iodide inserted zinc and was quenched with D2O at low temperature to give the trans-monodeuterated product (Equation 3.9) [82], 

Active zinc is an effective mediator in intramolecular conjugate additions. For example, a spirodecanone was formed from the 1,4-addition of the organozinc reagent, which was readily available from the primary iodide (Equation 3.10) [50]. Other types of ring closures also occur (Equations 3.11 and 3.12) and are thought to proceed by a mechanism that does not involve a free radical pathway. 

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