Acyclic magnesium carbenoid

Functionalized acyclic magnesium carbenoids can be prepared in THF/N-butyl-pyrrolidinone (NBP) mixtures at low temperatures. Thus, the reaction of the bis-iodomethylcarboxylate 254 with iPrMgCl in THF NBP is complete within 15 min at -78 °C. [133]. The resulting chiral bts-carbenoid 255 is quenched with PhSSPh giving the fois-adduct 256 in 70% yield (Scheme 4.53) [133]. 

Scheme 4.53 Preparation of functionalized acyclic magnesium carbenoids.

The /3-oxido carbenoid rearrangement then took place to give one-carbon expanded magnesium enolate having a chlorine atom (217), which was treated with water to afford a-chloroketone (218) in moderate yield. Unfortunately, this method could not be applied to larger cycloalkanones and acyclic ketones. Application of this method to aldehydes gave chloromethyl aryl ketones and chloromethyl alkyl ketones in moderate yields. ... 

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