- CHEMISTRY OF ENOL ETHERS. LXXXVI. DIENE CONDENSATION OF 2-TRIMETHYLSILYLOXY-1,3-DIENES WITH α,β-UNSATURATED ALDEHYDES. 1-FORMYL-4-TRIMETHYLSILYLOXY-3-CYCLOHEXENES AND 1-FORMYL-4-OXOCYCLOHEXANES
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The diene condensation of a series of 2-trimethylsilyloxy-1,3-dienes (2-trimethylsilyloxy-1,3-butadiene, 2-trimethylsilyloxy-1,3-pentadiene, 2-trimethylsilyloxy-4-methyl-1,3-pentadiene) with acrylaldehyde and crotonaldehyde is distinguished by high regioselectivity and low stereoselectivity.The "para" adducts (1-formyl-4-trimethylsilyloxy-3-cyclohexenes) are formed exclusively in all cases, and the reaction leads to the formation of a mixture of the cis and trans isomers with respect to the asymmetric centers.Alcoholysis or acid hydrolysis of 1-formyl-4-trimethylsilyloxy-3-cyclohexenes give high yields of 1-formyl-4-oxocyclohexanes.In a number of cases the diene condensation is accompanied by the formation of undesirable side compounds, produced as a result of transsilylation, which takes place between the 2-trimethylsilyloxy-1,3-diene and crotonaldehyde used in the reaction.
- Makin, S. M.,Shavrygina, O. A.,Nguyen, Fong Tung
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p. 2082 - 2087
(2007/10/02)
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