A recent attempt to selectively control the dehydrative spirocyclization of a
dihydroxyketone using a chiral-directing element has been reported by Paley
et al. [51]. Incorporation of an iron(0)-tricarbonyl diene complex into the
dihydroxyketone skeleton was used to direct spirocyclization (Scheme 6). Thus,
the unsubstituted spiroacetals 18 and 19 were obtained selectively in high yield
from the dehydrative spirocyclization of sulfinyl iron(0) diene complexes 16 and
17, respectively.
The results were more complex for substrates containing an additional chiral
element (i.e., 20a–d) (Scheme 7). These differences were attributed to
Scheme 6 Paley et al.’s use of an iron(0)-tricarbonyl diene as a chiral-directing element [51]
Scheme 7 Paley et al.’s use of an iron(0) tricarbonyl diene for spirocyclization in the presence of
an existing chiral center [51]
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M.A. Brimble and L.A. Stubbing