4-isopropyl-2-cyclohexenone

Highly uMtr-diastereofacial selective cycloaddition of isoprene (2) with 4-isopropyl-2-cyclohexenone allowed a short regiocontrolled and stereocon-trolled synthesis [13] of jS-cadinene and (y2-cadinene, Scheme 3.3). High anti-diastereofacial selectivity also occurs in the Diels-Alder reaction of optically active cyclohexenones 6-9 (Figure 3.2), readily available from the chiral pool, with open chain dienes [14-16]. Their cycloadducts are valuable intermediates in the synthesis of optically active sesquiterpenes in view of the easy conversion of the gem-dimethylcyclopropane and gem-dimethylcyclobutane in a variety of substituents. 

Photocyclization of allene and rac-4-isopropyl-2-cyclohexenone provides a 2 1 mixture of stereoisomers with two new stereogenic centers106 (see p 481 for configurational assignment). 

The Meerwein-Ponndorf Verley reduction of 4-isopropyl-2-cyclohexenone yields a mixture of pseudoaxial and pseudoequatorial alcohols, the trans configuration being favored [d.r. (cis/trans) 35 65]171. 

An useful intermediate for the preparation of 1,4-cyclohexanediones is obtained by cycloaddition of 6-isopropyl-3-methyl-2-cyclohexenone to a cyclobutanediol derivative (4.59) 470>. 

In a study of the photoisomerization of 4,4-dimethyl-2-cyclohexenone (8) to 6,6-dimethylbicyclo[3.1.0]-hexane-2-one (9) and 3-isopropyl-2-cyclo-pentenone (10), Chapman and Wampfler48 accounted for the pronounced effect of sensitizer concentration by such a self-quenching mechanism. The phenomenon was exhibited by four ketones with () lowest triplet states but not by benzophenone or acetophenone which have (w, n) triplet states.49... 

Coupling our own methodology with research developed by Wender et al.25 allowed us to devise a five-step sequence for the preparation of the cyclialkylation precursor 63 (Scheme 5.6). In the first step, the organolithium species 60 derived from isopropyl-veratrole24 was used to prepare cyclohexenone 61 through reaction with epoxide 59.25 The... 

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). 

Methyl-3-cyclo- (R )-2,3-Dihydroxypropanal 5-Isopropyl-2-methyl-hexenone (D-Glyceraldehyde) 2-cyclohexenone... 

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