for the most thermodynamically stable isomer. These methods have been reviewed
recently [2, 16].
2 Recent Advances and Application in the Synthesis of
5,6- and 6,6-Spiroacetals
2.1 Dehydrative Spirocyclization of a Dihydroxyketone
Dehydrative spirocyclization of a dihydroxyketone (Scheme 2) leads to the thermodynamically most stable spiroacetal as the major isomer. As discussed earlier, in
most cases this also corresponds to the doubly anomerically stabilized spiroacetal.
Scheme 1 Overview of methods for the synthesis of spiroacetals
Scheme 2 Dehydrative spirocyclization of a dihydroxyketone
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M.A. Brimble and L.A. Stubbing