Tert-Butyl isopropyl ketone

The reversibihty of carbonyl allylation reactions was initially discovered in the reaction of crotylmagnesium bromide with tert-butyl isopropyl ketone... 

Aliphatic Ketones The asymmetric hydrogenation of simple aliphatic ketones remains a challenging problem. This may be attributed to the difficulty with which the chiral catalyst differentiates between the two-alkyl substituents of the ketone. Promising results have been obtained in asymmetric hydrogenation of aliphatic ketones using the PennPhos-Rh complex in combinahon with 2,6-lutidine and potassium bromide (Tab. 1.11) [36]. For example, the asymmetric hydrogenation of tert-butyl methyl ketone affords the requisite secondary alcohol in 94% ee. Similarly, isopropyl, Butyl, and cyclohexyl methyl ketones have been reduced to the corresponding secondary alcohols with 85% ee, 75% ee, and 92% ee respectively. 

Suitable inert solvents include methyl ethyl ketone, benzene, ethylbenzene and toluene. Suitable initiators include peresters and peroxycarbonates such as ferf-butyl perbenzoate, ferf-butyl peroxy isopropyl carbonate, fcrf-butyl peroctoate, tert-butyl peroxy isonon-... 

Tetrahydrobenzo[6]thiophen-4-one (103) may be prepared from y-(2-thienyl)butyric acid by cyclization with phosphoric acid854 or by Friedel-Crafts cyclization of the corresponding acid chloride.194, 355.358 j s 5-methyl,357 2-ethyl,194 2-isopropyl,358 2- and 3-tert-butyl,359 2,3-dimethyl,360 2-ethyl-3-methyl,360 and 2-bromo 354 derivatives and diethyl 4,5,6,7-tetrahydrobenzo[6]thiophene-4,5-di-carboxylate861 may be prepared similarly. 4,5,6,7-Tetrahydrobenzo-[6]thiophen-7-one (104)357 362,863 and its 5- and 6-methyl 357 and 2-chloro 362 derivatives are obtained from the appropriately substituted y-(3-thienyl)butyric acid, A recent patent 364 describes the vapor phase cyclization of y-(2-thienyl)butyric acid to 103. Ketones (103 and 104) are useful intermediates for the synthesis of 4- and 7-substituted benzo[6]thiophenes, respectively their reactions are discussed in Section VI, B, 4. 

Irradiation of 4,4-dimethyl-2-cyclohexenone (Formula 83) in tert-butyl alcohol gives 6,6-dimethylbicyclo[3.1.0]hexan-2-one (Formula 84) in good yield with small amounts of 3-isopropyl-2-cyclopentenone (Formula 85) (46). The 3-isopropyl-2-cyclopentenone is formed by photochemical rearrangement of the bicyclic ketone (Formula 84) (46). 

Unlike acetone, diethyl ketone cleaves well even in cumene 22>. 2-Pentanone triplet undergoes considerable a-cleavage in competition with rapid intramolecular hydrogen abstraction, as judged by the buildup of an efficient triplet quencher 23>. Biacetyl is the only likely candidate for that quencher and is the major product of a-cleavage of methyl ketones at temperatures low enough that decarbonylation of the acetyl radical is slow. Isopropyl, tert-butyl, and benzyl ketones all cleave quite efficiently and various reports have appeared on the CIDNP spectra of products derived from the radicals 24>. 

C8H1802 methyl ethyl ketone peroxide 1338-23-4 478.13 41.787 2 15651 C8H19N N-isopropyl-N-methyl-tert-butyl amine 85523-00-8 400.15 31.116 1,2... 

---