Robinson Annulation Mechanismbetween 2 Methylcyclohexene And Methyl Vinyl Ketone

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Robinson annulation mechanismbetween 2 methylcyclohexene and methyl vinyl ketone.

Investigation in the field of stereochemistry of polycyclic compounds monoesters of cis and trans 1 methyl 1 2 cyclohexanedicarboxylic acids or 1 methyl 4 cyclohexene 1 2 dicarboxylic acids and their conversion. 3 methyl 2 cyclohexen 1 one exists as a solid slightly soluble in water and an extremely weak acidic. Robinson annulation is a fundamental organic reaction in particular because it is at the base of the synthesis of steroids and other important molecules even of pharmaceutical interest. Cyclohexenones are compounds containing a cylohexenone moiety which is a six membered aliphatic ring that carries a ketone and has one endocyclic double bond.

The cyclodehydration of 3 catalyzed by l proline is then performed at 25 c by simple stirring under argon for 120 h. The newly formed enolate intermediate must first tautomerize for the conversion to continue. The annulation reaction has as its most common substrates generally cycle hexanone and methyl vinyl ketone. Michael addition of cyclohexanones to methyl vinyl ketone followed by intramolecular aldol condensation to afford six membered α β unsaturated ketones.

In a second step the methyl group adjacent to the carbonyl is deprotonated and undergoes an. The optimized procedure 6 2 methyl 2 3 oxobutyl 1 3 cyclohexanedione 3 is prepared by heating 2 methylcyclohexane 1 3 dione 2 with methyl vinyl ketone 1 in aqueous acetic acid at 75 c for 1 h after which 3 is purified. As illustrated in the following figure the robinson annulation reaction involves two steps the first step involves the michael addition of a ketone enolate the enolate derived from cyclohexanone in the example pictured below to an alpha beta unsaturated ketone methyl vinyl ketone below. 1 michael addition 2 intramolecular aldol condensation.

2 methylcyclohexanone exists as a liquid slightly soluble in water and an extremely weak basic essentially neutral compound based on its pka. The journal of organic chemistry 45 p. Mechanism of the robinson annulation. Pubmed the action of t butyl hypochlorite on 1 methyl 4 isopropyl 3 cyclohexene p menthene 3.

2 methylcyclohexanone also known as fema 3946 or tetrahydro o cresol belongs to the class of organic compounds known as cyclic ketones. These are organic compounds containing a ketone that is conjugated to a cyclic moiety. 2 methylcyclohexanone is a cyclic ketone that is reported to occur in mint and horse chestnut.