Diels-Alder reaction unsymmetrical reagents

Ethoxy)-allylidenecyclopropane (136a) readily underwent Diels-Alder reaction with activated dienophiles under mild conditions (Table 14) [33]. Only one regioisomer was formed with unsymmetrically substituted dienophiles such as methyl maleic anhydride (137), and quinones 138-141 (entries 2 and 3-6). AH the cycloadducts 143-147 derive from an endo approach between the two reagents. Two site-isomers were obtained in 96 4 ratio with 3-isopropyl-6-methyl-p-quinone (141) (entry 6) and the high site-selectivity observed in this... 

IB Diels-Alder Reactions Using Unsymmetrical Reagents... 

Q Predict the products of Diels-Alder reactions, including the orientation of cycloaddition with unsymmetrical reagents and the stereochemistry of the products. 

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