Reactions of Chiral 2-(tert-Butyl)-2H,4H-1,3-dioxin-4-ones Bearing Functional Groups in the 6-Position and Diastereoselective Catalytic Hydrogenation tocis-2,6-Disubstituted 1,3-Dioxan-4-ones
作者:Yoshihiro Noda、Dieter Seebach
DOI:10.1002/hlca.19870700819
日期:1987.12.16
(R)-5-Bromo-6-(bromomethyl)-2-(tert-butyl)-2H,4H-1,3-dioxin-4-one (2) derived from (R)-3-hydroxybutanoic acid is used for substitutions and chain elongations at the side-chain C-atom in the 6-position of the heterocycle (3–6, 10–13). Subsequent simultaneous reductive debromination and double-bond hydrogenation (Pd/C,H2)occurs with essentially complete diastereoselectivity (>98% ds), with H transfer from
(R)-5-溴-6-(溴甲基)-2-(叔丁基)-2 H,4 H -1,3-二恶英-4-酮(2)衍生自(R)-3-羟基丁酸用于置换和链伸长在杂环(的6位上的侧链C-原子3-6,10-13)。随后发生的同时还原性脱溴和双键加氢(Pd / C,H 2)基本上完全是非对映选择性(> 98%ds),并且H从与t- Bu组相反的一侧转移(15–20,表1))。然后,二恶烷酮的水解裂解产生对映体纯的β-羟基酸衍生物(3-羟基丁酸的立体中心整体自我复制或在该酸的4-位烷基化并保留构型)。