Formation of Alcohols, Aldehydes and Ketones

The functional group transforms for the alkene to ketone conversion are  

Another route to tertiary alcohols involves monomethylborane (MeBH2), which can be prepared from lithium methylborohydride (LiMeBH3). 3l Reaction of MeBH2 with 2 equivalents of 1-hexene gave 185. Carbonylation and oxidation gave a 1 1 mixture of 186 and 187.131 When 10 equivalents of 1-hexene were used and the hydroboration was done at -25°C (in THF), carbonylation and oxidation gave 186 in 96% yield. 31 Ketones rather than alcohols can be synthesized if the carbonylation step is done in the presence of 

A pressure of 70 atmospheres of CO is required since hindered boranes, especially thexylborane, react sluggishly at atmospheric pressure. However, thexylborane reacted with cyclopentene to generate 188, and subsequent reaction with O-acetyl-hept-6-en-l-ol gave the trialkylborane (189). Carbonylation in the presence of water followed by oxidation gave the mixed ketone (190) in 73% yield. 33 In a similar manner, dienes can be transformed into the corresponding cyclic ketones. 34,135 

The functional group transforms in this section are quite useful and are outlined below  

Borane, monoalkylboranes and dialkylboranes (such as thexylborane and 9-BBN) were shown to be powerful reducing agents for carbonyl derivatives (sec. 4.6.A). When the B—H unit is removed, as in trialkylboranes, addition to the alkene moiety of a,p-unsaturated ketones or aldehydes occurs. An alkyl group of the borane is transferred to the terminal position of the alkene moiety (1,4-addition) and boron is transferred to the oxygen, giving a boron enolate (sec. 9.4.D). Initial hydroboration of acrolein with tricyclopentylborane gave boron enolate 196.1 0 

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The resulting complex mixtme of hydrocaibons is then separated into various fractions. The process also results in the formation of alcohols, aldehydes, and ketones. 

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