Chiral hypervalent iodine-catalyzed enantioselective oxidative Kita spirolactonization of 1-naphthol derivatives and one-pot diastereo-selective oxidation to epoxyspirolactones

We demonstrate here the rational design of a conformationally flexible C-2-symmetric iodosylarene 8g based on secondary n-sigma* or hydrogen-bonding interactions as a chiral catalyst for the enantioselective Kits oxidative spirolactonization of 1-naphthol derivatives 5. Iodosylarenes 8 were generated in situ from iotioarenes 7 and mCPBA as a co-oxidant. Furthermore, epoxyspirolactone 15 was obtained by the one-pot oxidation of 5 with mCBPA in the presence of 7g. Thus, the enantioselective oxidation of 5 to 6 and the successive enantio- and diastereo-selective oxidation of 5 to 15 proceeded in good yields when we controlled the amount of mCPBA. (C) 2010 Elsevier Ltd. All rights reserved.