Stereoselective Synthesis of (+)-Nephrosteranic Acid, (+)-trans-Cognac Lactone, and (+)-trans-Whisky Lactone using a Chiral Cyclohexadienyl Ti Compound
作者:Florian Schleth、Thomas Vogler、Klaus Harms、Armido Studer
DOI:10.1002/chem.200400237
日期:2004.9.6
3-dioxolandimethanol) cyclohexadienyl Ti derivative with various aldehydes led to the corresponding homoallylic alcohols with excellent diastereo- and enantioselectivities. Lower selectivities were obtained with chiral B-cyclohexadienyldiisopinocampheylborane. The 1,3-cyclohexadienes are very useful building blocks for the preparation of biologically important gamma-butyrolactones. Short efficient syntheses of (+)-nephrosteranic
我们提出了环己二烯从3金属1,4-环己二烯到各种醛的立体选择性转移。路易斯酸介导的醛的“烯丙基化”通过3-甲硅烷基化和3-苯乙烯基化的1,4-环己二烯的处理不能以高非对映选择性实现。相反,环己二烯基钛化合物与脂族和芳族醛的反应均具有优异的非对映选择性。手性TADDOL衍生的(TADDOL,2,2-二甲基-α,α,α',α'-四苯基-1,3-二氧代兰二甲醇)环己二烯基Ti衍生物与各种醛的反应导致相应的均丁醇具有出色的非对映体和对映选择性。用手性B-环己二烯基二异硫代樟脑硼烷获得较低的选择性。1 3-环己二烯是制备生物学上重要的γ-丁内酯的非常有用的结构单元。描述了通过1,4-环己二烯的不对称化来短效地合成(+)-肾甾酸,(+)-反式威士忌内酯和(+)-反白兰地内酯。