Synthesis of Natural Fragrant Molecules <i>cis</i>-3-Methyl-4-decanolide and Aerangis Lactone. General Enantioselective Routes to β,γ-<i>cis</i>-Disubstituted γ-Lactones and γ,δ-<i>cis</i>-Disubstituted δ-Lactones
作者:Yikang Wu、Xin Shen、Chao-Jun Tang、Zhi-Long Chen、Qi Hu、Wei Shi
DOI:10.1021/jo025540o
日期:2002.5.1
(S)-phenylalanine-derived 2-oxazolidinone or thiazolidinethione as chiral auxiliary, whereas the (S,S) ones were constructed with auxiliary prepared from (R)-phenylglycine. NaBH(4)/CaCl(2)/THF in the presence of a small amount of EtOH was introduced as a new effective method for reductive cleavage of chiral oxazolidinone auxiliaries. Previously unknown, tricky concentration effects were observed during the monotosylation
报告了使用TiCl(4)介导的Evans不对称醛醇缩合作为关键步骤的3,4-顺式-二烷基取代的γ-内酯和4,5-顺式-二烷基取代的δ-内酯的一般对映选择性途径。合成例举有两个天然的芳香分子,顺式-3-甲基-4-癸内酯(1)和Aerangis内酯(2)。使用(S)-苯丙氨酸衍生的2-恶唑烷酮或噻唑烷硫酮作为手性助剂建立(R,R)立体异构中心,而(S,S)则是由(R)-苯基甘氨酸制备的助剂构建的。NaBH(4)/ CaCl(2)/ THF在少量EtOH的存在下被引入作为还原性裂解手性恶唑烷酮助剂的新有效方法。以前未知,在二醇7的单甲苯基化和Evans aldol 23的BOM保护期间观察到棘手的浓度影响。