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Ketone, diisopropyl aldol reaction

AUol condensations. This triflate, in combination with a base (diisopropyl- Ihylamine), is useful for cross-aldol reaction of ketones with aldehydes. Examples ... [Pg.296]

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. [Pg.144]

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. [Pg.387]

Condensation Reactions. Boron trichloride converts ketones into (Z)-boron enolates at —95 °C in the presence of Diisopropyl-ethylamine. These enolates react with aldehydes with high syn diastereoselectivity (eq 2). A similar condensation of imines with carbonyl compounds also provides crossed aldols in reasonable yields. The reaction was extended to the asymmetric aldoi condensation of acetophenone imine and benzaldehyde by using isobornylamine as a chiral auxiliary (48% ee). ... [Pg.67]

The most successful imide systems for diastereoselective aldol addition reactions are, without question, the oxazolidinones 50-52 developed by Evans. These furnish syn aldol adducts with superb selectivity for a broad range of substrates (Scheme 4.5) [6, 13, 45-47). A hallmark of these system is that enolization yields exclusively the Z-enolates, which can be understood on the basis of steric considerations. Two important discoveries in the area proved critical to the unparalleled success enjoyed by Evans auxiliaries for diastereoselective aldol addition reactions. The first of these was the disclosure by Mukaiyama that the combination of di-n-butylboryl trifluorometh-anesulfonate (n-Bu2BOTf) and diisopropyl ethyl amine can be employed for the generation of dialkylboron enolates from ketones [48]. The second key observation was by Roster, who observed that aldol additions of boron enolates proceeded with higher levels of simple induction [49], This phenomenon is attributed to the short B-0 distances in the attendant Zimmer-man-Traxler transition state structure [14, 47]. [Pg.107]


See other pages where Ketone, diisopropyl aldol reaction is mentioned: [Pg.27]   
See also in sourсe #XX -- [ Pg.2 , Pg.144 ]

See also in sourсe #XX -- [ Pg.2 , Pg.144 ]




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Diisopropyl

Diisopropyl ketone

Ketones aldol reactions

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