Asymmetric [2,3]-Wittig Rearrangement of Oxygenated Allyl Benzyl Ethers in the Presence of a Chiral di-<i>t</i>Bu-bis(oxazoline) Ligand: A Novel Synthetic Approach to THF Lignans
作者:Maria Kitamura、Yoshimi Hirokawa、Naoyoshi Maezaki
DOI:10.1002/chem.200901212
日期:2009.9.28
allyl benzyl ethers in the presence of a chiral di‐tBu‐bis(oxazoline) ligand. In various oxygenated benzylic ethers, the reactions proceeded with excellent diastereo‐ and enantioselectivities, although the presence of a methoxy substituent at the ortho‐position on the benzyl group drastically decreased the enantioselectivity. Conversely, o‐ethyl and o‐phenyl substituents had no significant effect on
我们已经在手性二-的存在下完成的官能化的烯丙基苄基醚高度对映选择性的[2,3] -Wittig重排吨卜双(恶唑啉)配体。在各种含氧苄基醚中,尽管苄基邻位存在甲氧基取代基会大大降低对映选择性,但反应仍具有出色的非对映选择性和对映选择性。相反,o-乙基和o-苯基取代基对选择性没有显着影响。我们发现,烯丙基部分的C2取代基在产生高对映选择性方面起着重要作用。还描述了在催化量的手性配体存在下高度对映选择性的[2,3] -Wittig重排。