Synthesis of the alkaloid tyroscherin by an aldol/Curtius strategy
作者:Markus Ugele、Martin E. Maier
DOI:10.1016/j.tet.2010.02.034
日期:2010.4
The alkaloid tyroscherin (2), which contains a vicinal anti-amino alcohol subunit was prepared from 4-hydroxyphenylpropionic acid (5) and meso-diol 9. After desymmetrization of diol 9 and suitable protectinggroup manipulations, one terminus was extended via a Claisen rearrangement giving rise to enoate ent-15. The missing carbon on the other end could be incorporated using MeMgCl/CuBr·SMe2 leading
Conversion of ester moieties into 4-bromophenyl groups was effected by means of a four-step protocol: a Grignard reaction of the ester with allylmagnesium halides, a ring-closing metathesis, dibromocyclopropanation, and an electrocyclicreaction of the dibromocyclopropanes.