Application of the β-azidonation reaction to the synthesis of the antitumor alkaloid (+)-pancratistatin
作者:Philip Magnus、Iyassu K. Sebhat
DOI:10.1016/s0040-4020(98)00975-2
日期:1998.12
gave the ketone29. Chirality was introduced by deprotonation of29 with the lithium salt of (+)-bis(α-methylbenzyl)amine, followed by triisopropylsilyl trifluoromethanesulfonate to give30 (95%). β-Azidonation of30 with (PhIO)n/TMSN3 rapidly produced31 (95%) as a mixture of trans- and cis- diastereomers in a 3.5:1 ratio. Reduction with LiAlH4 followed by methyl chloroformate/pyridine gave32, which on
按照文献程序将邻香兰素21转化为24。用正丁基锂/ THF处理24,随后添加25,得到26。脱水(POCl 3 /吡啶/ DBU),氢化和水解26得到酮29。通过用(+)-双(α-甲基苄基)胺的锂盐使29去质子化,然后再用三异丙基甲硅烷基三氟甲磺酸盐进行去质子化反应而得到手性,得到30(95%)。用(PhIO )n / TMSN 3进行30的β-叠氮反应可快速生成31(95%)的混合物反式-和顺-在3.5非对映体:1的比例。用LiAlH 4还原,然后用氯甲酸甲酯/吡啶还原,得到32,经MCPBA / CH 2 Cl 2 /咪唑处理,得到33。的水解33得到34,其当暴露于甲部吨在90 / HMPA℃下导致39。将39转化为烯酮42后,用NaHCO 3 / H 2 O 2 / MeOH环氧化得到43。减少43将其与L-selectride反应,然后与苯甲酸钠在水中溶剂化,得到46,将其立即乙酰化,得到47。内酰胺的形成(Tf