Synthesis of nonracemic 2,3,6-trisubstituted piperidine derivatives from sugar lactones via tandem Wittig [2+3] cycloaddition reaction. A novel entry to Prosopis and Cassia alkaloids
作者:Claus Herdeis、Thomas Schiffer
DOI:10.1016/s0040-4020(98)01085-0
日期:1999.1
azido lactol 7 proceeds with concomitant 1,3-dipolar cycloaddition of the azido function to the α, β-unsaturated ester function of 9a,b which can not be isolated. The diastereomeric triazolines 10a,b and the diazoamines 11a,b were separated. The vinylogous urethane 13 can be hydrogenated diastereoselectively to the all-cis configurated piperidyl acetic ester derivative 14 which is deprotcted to 1. Functional
叠氮基乳糖醇7的维蒂希反应与叠氮基官能团的1,3-偶极环加成反应到无法分离的9a,b的α,β-不饱和酯官能团上进行。分离非对映体三唑啉10a,b和重氮胺11a,b。乙烯基氨基甲酸酯13可以非对映选择性地氢化为被保护为1的全顺式构型的哌啶基乙酸酯衍生物14。侧链的官能团转化是通过双环氨基甲酸酯15完成的,该双环氨基甲酸酯15被转化为3-羟基二氢吡啶20。