Diels Al Lewis acids mediate

Barriault et al. demonstrated the Lewis acid-mediated triple domino Diels-Alder/ Prins/Pinacol reactions [22], which were utilized for the construction of highly functionalized bicyclo[m.n.l]alkanones [23]. Some tetra-fused carbocycles were efficiently produced from the corresponding cycloadducts generated in situ by the Diels-Alder reaction of 2,2-dimethyl-1,3-dioxolanes having a diene moiety at C4 position with dienophiles (Scheme 10.6). 

Despite remarkable progress in catalytic asymmetric Diels-Alder reactions using various chiral Lewis acid catalysts [51], only a limited number of chiral catalysts effectively mediate quinone Diels-Alder reactions with moderate to good enantioselectivity [56]. Evans et al. reported that Sm(OTf)3- and Gd(OTf)3-PyBOX 

As shown in Scheme 24, the ABD tricyclic core was prepared in low yield by Simpkins et al. using a Lewis-acid mediated Diels-Alder cycloaddition that leads to a functionalized c/5-hydroisoquinoline. Additional 

Tamariz et al. developed an access to 1-methoxycarbazoles 225 via hydrolysis of 3-arylbenzoxazol-2-ones 223 and subsequent palladium(II)-mediated oxidative cyclization of the resulting diarylamines 224 (Scheme 54) [213, 214]. The required benzoxazol-2-ones 223 are obtained by regioselective Lewis acid-catalyzed Diels-Alder reaction of 4,5-dimethylene-3-aryl-l,3-oxazolidm-2-ones with alk-enes followed by aromatization using 2,3-dichloro-5,6-dicyano-l,4-benzoquinone (DDQ). 

---