Ketone, diisobutyl aldol reaction

Whereas a lower temperature is essential to mediate deprotonation with DATMP, diisobutyl aluminum phenoxide requires quite a high temperature (THF, reflux) to generate the aluminum enolates, with the aid of a shght excess of pyridine (Scheme 6.24) [44], Self aldol condensation of ketone 47 proceeded with acceptable yield under these conditions. An efficient synfhesis of tfl-muscone was achieved by way of an intramolecular aldol reaction by use of these reagents. 

Pentanone is similar to acetone in its behavior, and 1 1 adducts may be obtained from aliphatic aldehydes in good yield (equations 47 and 48). 4-Heptanone and higher symmetrical ketones are much less reactive and give very poor yields of aldols with simple aldehydes. However, the reactions of these ketones with o-phthalaldehyde often provide benzotropone derivatives in excellent yield (e.g. equation 49). Diisopropyl ketone and diisobutyl ketone do not give mixed adducts with aldehydes under tte normal protic conditions. 

Firstly, we have the acetone aldol self-condensation reaction over basic sites to give diacetone alcohol (DAA). Dehydration of this alcohol yeilds mesityl oxide (MSO) winch, in turn, can be selectively hydrogenated over reduced metal sites to finally give methyl isobutyl ketone (MIBK). In addition to the aldol condensation route, the acetone carbonyl functional group can also be directly hydrogenated over reduced metal sites yielding 2-propanol. Other reaction by-products such as methane, propane, diisopropyl ether and diisobutyl ketone have been detected in some experiments, but in very low amounts, lower than 2% of the total reaction products. 

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See also in sourсe #XX -- [ , ]

See also in sourсe #XX -- [ , ]

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