[GRAPHICS]The PdCl2-catalyzed cyclization of alpha-alkoxy dienones leads to 2-hydroxycyclopentenones, whereas the Pd(OAc)(2)-catalyzed reaction leads to cross-conjugated cyclopentenones through an oxidative process.
A Brønstedacid‐catalyzed asymmetricNazarovcyclization of acyclic α‐alkoxy dienones has been developed. The reaction offers access to chiral cyclopentenones in a highly enantioselective manner. The reaction is complementary to our previously reported Brønstedacid‐catalyzed electrocyclization reactions, which provided differently substituted optically active cyclopentenones with a fused tetrahydropyrane
[GRAPHICS]The PdCl2-catalyzed cyclization of alpha-alkoxy dienones leads to 2-hydroxycyclopentenones, whereas the Pd(OAc)(2)-catalyzed reaction leads to cross-conjugated cyclopentenones through an oxidative process.
Enantioselective Nazarov Cyclizations Catalyzed by an Axial Chiral C<sub>6</sub>
F<sub>5</sub>
-Substituted Boron Lewis Acid
A chiral variant of B(C6F5)3 with a 3,3′‐disubstituted binaphthyl backbone is shown to catalyze Nazarov cyclizations with high levels of enantio‐ and diastereocontrol. The parent B(C6F5)3 also promotes these ring closures efficiently. This electrocyclization is another example of the still small family of C−C bond formations mediated by B(C6F5)3 as the catalyst.
具有3,3'-双取代的联萘骨架的B(C 6 F 5)3的手性变异体可催化Nazarov环化反应,并具有高水平的对映和非对映控制。母体B(C 6 F 5)3也有效地促进了这些环的闭合。这种电环化是由B(C 6 F 5)3作为催化剂介导的C-C键形成家族仍然很小的另一个例子。