1999 stereochemistry

stereochemistry (general, optical resolution)O 0030

25 - 030Stereoselective Synthesis of Silyl Enol Ethers via the Iridium-Catalyzed Isomerization of Allyl Silyl Ethers. — TreatingIr(cod)(PMePh2)2PF6 with catecholborane or Ir(cod)2PF6/PBu3 (or PPr3)(1:2) with hydrogen generates in situ a cationic iridium (I) complex. The latteris an excellent catalyst for achieving high yields and high stereoselectivity inthe isomerization of primary allyl silyl ethers, e.g. (I), to give E-enol ethers, e.g.(II), and of secondary allyl silyl ethers, e.g. (III) and (VI), to give Z-enol ethers,e.g. (V) and (VII), under mild conditions. — (OHMURA, TOSHIMICHI;YAMAMOTO, YASUNORI; MIYAURA, NORIO; Organometallics 18 (1999)3, 413-416; Div. Mol. Chem., Grad. Sch. Eng., Hokkaido Univ., Sapporo 060,Japan; EN)

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