Preparation of tertiary Grignard reagents

Has anyone a good and detailed experimental procedure to prepare tertiary Grignard reagents from tertiary alkyl halides on the lab scale (1-5 mmol)? The actual procedures in the literature are very scarce and limited to patents (large amounts). Older procedures exist only for tBuMgCl and not after 1932.




Sterically hindered GRs are hard to make as @matt\_black mentioned and although its synthesis looks single step and straight forward, most literature leaves bits out. I did find a recent publication where they mentioned the steps:



> 
> ***tert*-butylmagnesium chloride**
> 
> 
> $$\ce{t-BuCl + Mg ->[I2,anhyd. Et2O] t-BuMgCl}$$
> 
> 
> In a 3L, three-necked, round-bottom flask, fitted with a mechanical stirrer and a Hg seal, a 500-mL separatory funnel, and an efficient reflux condenser, were placed Mg turnings or powder (144g, 6.0 mol). The Mg was then covered with anhyd. $\ce{Et2O}$ (400 mL). Pure $\ce{t-BuCl}$ (~5 mL, with a crystal of $\ce{I2}$) was added to start the reaction. Stirring was begun and a solution of pure $\ce{t-BuCl}$ (555g, 6.0 mol) in anhyd. $\ce{Et2O}$ (1.5 L) was dropped slowly onto the Mg during 6-8 h. The reaction was practically complete when all of the halide had been added, but stirring was continued for further 15 min.
> 
> 
> Science of Synthesis: Houben-Weyl Methods of Molecular Transformations Vol. 7: Compounds of Groups 13 and 2 (Al, Ga, In, Tl, Be...Ba), Georg Thieme Verlag, **2014**
> 
> 
> 


Alternatively, you can look at the [orgsyn article](http://www.orgsyn.org/demo.aspx?prep=CV1P0524) or this [2001 WOL article](https://onlinelibrary.wiley.com/doi/10.1002/047084289X.rb399) but the steps/reagents are more or less same.


 1