Reaction With Alcohols Synthesis of Chlorides

An alternative route to II is the direct reaction of alkoxide ion with dichlorocarbene. In any event, once formed, II can undergo protonation and hydrolysis to yield a formate ester or it can lose chloride (a-elimination) to form an alkoxychlorocarbene (III). The alkoxychlorocarbene (III) can then either expel carbon monoxide via an Sisii type reaction or lose CO sequentially. The alkyl chloride results from ion pair collapse. This sequence is illustrated in equation 3.3. 

1-adamantyl methyl alcohol i 1-adamantyl methyl chloride j 40 

The phase transfer carbene reaction with methanol, 1- and 2-propanol, r-butanol and cyclohexanol is not successful, leading to complex product mixtures. Ethanol and 2,2,2-trifluoroethanol, on the other hand, yield the corresponding orthoformates in 36% and 33% yields respectively [8]. The transformation is formulated in equation 3.4. 

The reaction of an allylic alcohol with dichlorocarbene is noted above and in Sect. 

11 to give products of cyclopropanation rather than the corresponding chloride [7]. In certain other cases, cyclopropanation of a molecule containing both a hydroxyl group and an olefin may lead to products of rearrangement and intramolecular reac- 

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