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Cyclohexenone ring

Dauben et al. have investigated the scope of the photochemical type A rearrangement/60 They conclude that the rearrangement occurs only if the fourth carbon atom of the 2-cyclohexenone ring is fully alkyl-substituted. If this requirement is not met, photodimers are the major products. This substituent requirement is necessary but not sufficient to ensure rearrangement since the presence of other groups can inhibit the reaction. [Pg.471]

All of the parts of this mechanism have been discussed in previous sections of Chapter 24. However, the end result of the Robinson annulation— the formation of a 2-cyclohexenone ring—is new. [Pg.937]

Step [1] Locate the 2-cyclohexenone ring and re-draw the target molecule if necessary. [Pg.939]

Step [2] Break the 2-cyclohexenone ring into two components. [Pg.939]

The first stage of a Robinson annulation is a Michael reaction that forms a 1,5-dike-tone. You just saw that a 1,5-diketone undergoes an intramolecular aldol addition when treated with base—this is the second stage of the Robinson annulation. Notice that a Robinson annulation results in a product that has a 2-cyclohexenone ring. [Pg.817]

Robinson annulation is a reaction sequence consisting of a Michael addition of a cycloalkanone a-carbanion to an a,[3-unsaturated ketone derivative, followed by al-dol condensation to form the final product, a 2-cyclohexenone ring fused to the... [Pg.54]

Cyclohexenone ring from phenolethers Birch reduction... [Pg.324]

Cyclohexenone ring from a,/ -ethyleneketones Stereospecific Robinson annelation Effect of solvent... [Pg.497]

Iron pentacarbony 1/irradiation 2-Cyclohexenone ring from cyclic vinylcyclopropanes... [Pg.184]

Perchloric acidlL-phenylalanine 2-Cyclohexenone ring from 1,5-diketones Asym. induction... [Pg.249]

Cyclohexenone ring from diketones Azeotropic water entrainment... [Pg.567]

Palladium-carhonlpotassium hydroxide Cyclohexanone from 2-cyclohexenone ring... [Pg.40]

Cyclohexenone ring from -aminoketones Robinson-Mannich base procedure Ring closure... [Pg.212]

Potassium hydroxide 2-Cyclohexenone ring closure with decarbalkoxylation... [Pg.223]

Cyclohexenone ring from a,y -ethyleneketones via Michael addition... [Pg.504]

See other pages where Cyclohexenone ring is mentioned: [Pg.936]    [Pg.262]    [Pg.266]    [Pg.224]    [Pg.226]    [Pg.230]    [Pg.202]    [Pg.210]    [Pg.243]    [Pg.275]    [Pg.277]    [Pg.278]    [Pg.295]    [Pg.300]    [Pg.561]    [Pg.311]    [Pg.311]    [Pg.311]    [Pg.317]    [Pg.354]    [Pg.418]    [Pg.647]    [Pg.648]    [Pg.229]    [Pg.192]    [Pg.235]    [Pg.238]    [Pg.279]   


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2-Cyclohexenone

Cyclohexenone ring of abscisic acid

Cyclohexenones

Cyclohexenones ring contraction

Vinylcyclopropanes 2-cyclohexenone ring

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