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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: g.bontempi on April 25, 2020, 10:37:00 AM

Title: Tertiary alcohol reaction with SOCl2 and pyridine
Post by: g.bontempi on April 25, 2020, 10:37:00 AM

With a primary or seconday alcohol the oxygen attacks the Sulphur and then with a SN2 mechanism the Cl- attacks and SO2Cl- acts as a leaving group, yielding an alkyl chloride.

My question is: why doesn't this mechanism work with tertiary alcohols? the second step could be a SN1 mechanism instead of SN2.

If SN1 really can't proceed, what would happen? the -OSOCl group just stays there?

Title: Re: Tertiary alcohol reaction with SOCl2 and pyridine
Post by: AWK on April 25, 2020, 11:01:23 AM

SNi mechanism.

Title: Re: Tertiary alcohol reaction with SOCl2 and pyridine
Post by: shivapharma on June 16, 2020, 03:15:35 AM

Most of the time, the reaction of alcohols with thionyl chloride is taught as an SN2 reaction. And indeed, on primary alcohols this is definitely the case. The problem arises with secondary alcohols, where the reaction can be taught either as a classical SN2 with inversion, or… as a reaction with retention.