Hydroxymethylation of Bis methylthio methane with Paraformaldehyde

The reaction of lithiated S,S-acetals with aldehydes and ketones is a well-established reaction and needs no exemplification by an experimental procedure. The reactions with most of the aldehydes and ketones are extremely rapid, even at temperatures in the region of — 80 °C. A number of examples have been mentioned in the reviews of Seebach [1,2]. 

In this experiment it is shown that a CH2OH group can be successfully introduced by reaction of the organolithium compound with (dry) paraformaldehyde [3]. For obtaining good yields of the corresponding alcohol, it appeared to be necessary to use a large excess (at least 400 mol%) of the polymeric aldehyde. 

A larger amount of the powder is heated for half an hour in a vacuum of 10 20 mmHg using a rotary evaporator and a bath heated at 60-70 °C. It is advisable to put the powder in a relatively big flask (0.5 to 1 liter). A trap cooled at — 78 °C is placed between the evaporator and the water aspirator. 

The polymer is added through a powder funnel which replaces the dropping funnel. 

Schaap A, Brandsma L, Arens JF (1967) Reel Trav Chim Pays-Bas 86 393 

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