Organic Reactions Volume 4 - Sciencemadness Dot Org

66 ORGANIC REACTIONS
1,1,3-Trimethylbutadiene and acrolein give a mixture of the two
possible isomers (XIV and XV) in about equal amounts. 5 From the
,CHO
H3C 1 H8C 1
XIV XV
CHO
products (X) of the reaction of 2-alkoxybutadienes and acrolein, 4ketocyclohexane-1-carboxylic
acid can be prepared by oxidation and
acid hydrolysis. 8
The addition of acrolein to cyclopentadiene has been shown to give
the endo-2,5-methano-A 3 -tetrahydrobenzaldehyde (XVI) - 1 Alder,
Stein, et al. 9 - 10 ' 11 have described the preparation of the hexahydro
XVI
derivative, its conversion to the corresponding exo aldehyde (by saponification
of the enol acetate formed from the endo aldehyde and acetic
anhydride), and the preparation of the acids, alcohols, and amines (by
Curtius degradation) of the two series. Norcamphor (XVII) has been
prepared from the 2,5-methanohexahydrobenzaldehyde.
Cyclohexadiene and acrolein give 2,5-ethano~A 3 -tetrahydrobenzaldehyde
(XVIII) in good yield. 12 Cinnamaldehyde and 2,3-dimethyl~
butadiene yield 4,5-dimethy ltetrahy dr obiphenyl~2~aldehy de (XIX,
CHO
H8C1
CH8
CHO
XVII
XYIII XIX XX
O
CHO
8 Fiesselmann, Ber., 75, 881 (1942) [C. A., 37, 3417 (1943)].
9 Alder, Stein, Schneider, Liebmann, Rolland, and Schulze, Ann., 525, 183 (1936).
1° Alder, Stein, and Rolland, Ann., 525, 247 (1936).
11 Alder, Stein, Rolland, and Schulze, Ann., 514, 211 (1934).
i 2 Diels and Alder, Ann., 478, 137 (1980).