2.4 Spirocyclization of an Endocyclic Enol Ether
Spirocyclization of an appropriately substituted dihydropyran under acidic conditions (Scheme 26) is another popular method for the synthesis of spiroacetals. The
dihydropyrans themselves are obtained via a variety of methods, the most recent of
which include Suzuki–Miyaura strategies [72–74]. Other recent developments of
Scheme 24 Yadav et al.’s synthesis of pteridic acid A [70]
Scheme 23 Jung et al.’s syntheses of auripyrones A and B [68, 69]
Synthesis of 5,6- and 6,6-Spirocyclic Compounds
207
Spirocyclization of an appropriately substituted dihydropyran under acidic conditions (Scheme 26) is another popular method for the synthesis of spiroacetals. The
dihydropyrans themselves are obtained via a variety of methods, the most recent of
which include Suzuki–Miyaura strategies [72–74]. Other recent developments of
Scheme 24 Yadav et al.’s synthesis of pteridic acid A [70]
Scheme 23 Jung et al.’s syntheses of auripyrones A and B [68, 69]
Synthesis of 5,6- and 6,6-Spirocyclic Compounds
207