Optically Active Epoxy Diols by Titanium-Catalyzed Oxidation of Enantiomerically Enriched Hydroperoxy and Hydroxy Homoallylic Alcohols
作者:Waldemar Adam、Marion N. Korb、Chantu R. Saha-Möller
DOI:10.1002/(sici)1099-0690(199805)1998:5<907::aid-ejoc907>3.0.co;2-f
日期:1998.5
The Ti-catalyzed epoxidation of optically active (S,S)-hydroperoxy homoallylic alcohols 2 affords the epoxy diol (S,R,S)-4 in high diastereoselectivity (d.r. up to 95:5), while the optically active hydroxy homoallylic alcohols (R,R)-3 are epoxidized by the β-hydroperoxy alcohol 5 under titanium catalysis to the corresponding epoxy (R,S,R)-diol 4 in a diastereomeric ratio up to > 99:1. This high diastereoselectivity
光学活性 (S,S)-氢过氧高烯丙醇 2 的 Ti 催化环氧化以高非对映选择性(dr 高达 95:5)提供环氧二醇 (S,R,S)-4,而光学活性羟基高烯丙醇(R,R)-3 在钛催化下被 β-氢过氧醇 5 环氧化成相应的环氧 (R,S,R)-二醇 4,非对映体比例高达 > 99:1。这种高非对映选择性在氧转移的刚性模板方面被合理化,其中氢过氧醇 2 或 5 三齿连接,二醇 3 双齿结合到钛金属。通过这些氧化途径,可以方便地获得两种对映体环氧二醇4。