Application of the β-azidonation reaction to the enantioselective synthesis of the lycorane Amaryllidaceae alkaloids
作者:Philip Magnus、James M. Bailey、Michael J. Porter
DOI:10.1016/s0040-4020(99)00850-9
日期:1999.12
The prochiral ketone 5 was treated with the lithium salt of (+)-bis(α-methylbenzyl)amine, followed by triisopropylsilyl trifluoromethanesulfonate to give 10 (96%). β-Azidonation of 10 with rapidly produced 11 (95%) as a mixture of trans- and cis- diastereomers in a 3.5:1 ratio. Reduction of 11 with LiAlH4 followed by gave 13. N-Alkylation of 13 with 1,2-dibromoethane followed by radical cyclization
用(+)-双(α-甲基苄基)胺的锂盐,然后用三异丙基甲硅烷基三氟甲磺酸盐处理前手性酮5,得到10(96%)。β-Azidonation 10与快速产生11(95%),为的混合物反式-和顺-在3.5非对映体:1的比例。用LiAlH 4还原11,随后得到13。用1,2-二溴乙烷将13进行N-烷基化,然后进行自由基环化,生成15,将其转化为二十烷酸衍生物22。22的绝对构型由对溴苯甲酸酯24的X射线晶体结构确定。