Organocatalytic aldol approach for the protecting group-free asymmetric synthesis of (7<i>R</i>′)-parabenzlactone, (−)-hinokinin, (−)-yatein, (−)-bursehernin, (−)-pluviatolide, (+)-isostegane and allied lignans
作者:Mainak Bera、Biswajit Sen、Sujay Garai、Saumen Hajra
DOI:10.1039/d3ob01446k
日期:——
efficient catalytic asymmetric protection-free synthesis of dibenzylbutyrolactone lignans, such as (−)-hinokinin, (−)-yatein, (−)-bursehernin, (−)-pluviatolide, and their 7′-hydroxylignans – (7′R)-parabenzlactone, (7′R)-hydroxyyatein, (7′R)-hydroxybursehernin, and (7′R)-hydroxy pluviatolide, respectively, is described. The syntheses of (+)-isostegane and the formal synthesis of (−)-podophyllotoxin and
二苄基丁内酯木脂素的短而高效的催化不对称无保护合成,例如(−)-hinokinin、(−)-yatein、(−)-bursehernin、(−)-pluviatolide及其7′-羟基木脂素 – (7′分别描述了R )-对苯甲内酯、(7'R ) -羟基叶黄素、(7'R ) -羟基花伞素和(7'R ) -羟基雨花内酯。还描述了 (+)-异牡丹烷的合成以及 (-)-鬼臼毒素和水葫芦素的正式合成。有机催化羟醛还原-内酯化和 Pd/C 催化氢化脱溴是用于对映选择性合成羟基丁内酯13b的两锅连续反应,具有优异的非对映选择性和对映选择性(dr 33 : 1 和 >99% ee)。13b的无保护基化学选择性α-烷基化直接生成7'-羟基二苄基丁内酯木脂素,然后氢化脱羟基,生成(脱氧)二苄基丁内酯木脂素,并且从6-溴胡椒醛经过三到五步完成合成。