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5845839 
Journal Article 
The revised stereostructures of the Diels-Alder adducts of 1-carvone with butadiene 
Harayama, T; Cho, H; Inubushi, Y 
1975 
1 
Tetrahedron Letters
ISSN: 0040-4039
EISSN: 1873-3581 
16 
31 
2693-2696 
English 
WOS:A1975AJ25600021 
has other version or edition 5637206 Revised stereostructures of diels-alder adducts of l-carvone with butadiene
On the Diels-Alder reaction of carvone with butadiene under heating conditions, Nerdel et al. reported that the stereostructure of the major product (in 6% yield) was shown by the formula (Ib) and that of the minor product (in 2% yield) by the formula (Ia).) This result suggested that addition of butadiene to the dienophile took place predominantly from the same side as that of an isopropenyl group. Recently, we examined the Diels-Alder reaction of 5-methyl-2-cyclohexene-l-one with butadiene in the presence of BF3 etherate and it was ascertained that addition of butadiene to the dienophile occurred opposite to a secondary methyl group. 2) The former result is, therefore, in conflicting with our conclusion prompting us to re-examine the stereostructures of the Diels-Alder adducts reported in the literature. 1) The contradiction has now been resolved by revision of the formulas reported in such a way that the structure (Ib) for the major product is replaced by the formula (Ia) and the structure (Ia) for the minor product by the formula (Ib).