Synthesis of 2-Methyl-<scp>d</scp>-erythritol via Epoxy Ester−Orthoester Rearrangement
作者:José-Luis Giner、William V. Ferris,、Joseph J. Mullins
DOI:10.1021/jo020168y
日期:2002.7.1
epoxy ester[bond]orthoester rearrangement has been applied to a new synthesis of 2-methyl-D-erythritol, a branched five-carbon sugar of importance to the deoxyxylulose pathway of isoprenoid biosynthesis. The intermediate orthoacetate is one of the few [2.2.1]-orthoesters to have been reported. Labeling studies with O-18 indicated that this reaction proceeds exclusively via a 5-exo cyclization. NMR analysis
New opticallyactive hydroxamic acids bearing a 1,1′-binaphthyl group were prepared as ligands in a vanadium-catalyzed asymmetricepoxidation. The feature of these hydroxamic acids is a sterically hindered ligand. The asymmetricepoxidation with good selectivity and reactivity can be established by using VO(O-i-Pr)3 (5 mol%) and a small excess amount of ligand (7.5 mol%) with triphenylmethyl hydroperoxide
在钒催化的不对称环氧化反应中,制备了带有 1,1'-联萘基团的新型旋光异羟肟酸作为配体。这些异羟肟酸的特征是空间位阻配体。在-20 °C 的甲苯中,使用 VO(Oi-Pr)3 (5 mol%) 和少量过量的配体 (7.5 mol%) 与三苯甲基氢过氧化物 (TrOOH) 可以建立具有良好选择性和反应性的不对称环氧化反应. 二取代的烯丙醇比单取代或三取代的烯丙醇环氧化得更快,并且以良好到高的对映选择性 (48-94%ee) 获得。讨论了基于 1e 的 X 射线晶体结构的过渡态。
MARSHALL, JAMES A.;TROMETER, JOSEPH D.;BLOUGH, BRUCE E.;CRUTE, THOMAS D., TETRAHEDRON LETT., 29,(1988) N 8, 913-916
作者:MARSHALL, JAMES A.、TROMETER, JOSEPH D.、BLOUGH, BRUCE E.、CRUTE, THOMAS D.