2-Methyl-4-(2,2,3-trimethylcyclopent-3-en-1-yl)but-2-enal → 3-Cyclopentene-1-butanal, .alpha.,2,2,3-tetramethyl-

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Reaction Steps

A mixture of 111 g (0.58 mole) of 2-methyl-4-(2,2,3-trimethylcyclopent-3-en-1-yl)but-2-enal, 2.7 g of 5% palladium on carbon and 80 ml of ethanol was hydrogenated at 30°-40° C and 40-55 psi until hydrogen uptake ceases. The mixture was filtered to remove the catalyst and the solvent removed by distillation. The residual oil was fractionally distilled to yield 2-methyl-4-(2,2,3-trimethylcyclopent-3-en-1-yl)butanal. Yield 110.7 g (98.4% theory); bp 60°-61° (1.4 mm); mol wt. 194 (ms); ir, 3040, 2700, 1728 (s), 800 cm-1 ; nmr, 0.5δ, 0.8, 0.9 and 1.0 (6H, 4 s, geminal dimethyl groups of various diastereomers in the mixture), 1.1 (3H, d, J~7 Hz), 1.3-2.6 (7H, broad complex), 1.6 (3H broad s, olefinic methyl), 5.2 (1 H, broad multiplet, olefinic H), 9.7 (1H, d, J~1.5 Hz, aldehyde H).

Provenance & Evidence