Synthesis of Conformationally Defined Analogues of Norfenfluramine. A Highly Stereospecific Synthesis of Amines from Alcohols in the Benzobicycloheptene System

Article abstract of DOI:10.1021/jo00162a005

The synthesis of 5-, 6-, 7-, and 8-(trifluoromethyl)benzonorbornen-2-yl alcohols 6a-9a (exo) and 11a-14a (endo) and an examination of the stereospecificity of the conversion to amines via phthalimides are reported.The exo alcohols were prepared from 5-(trifluoromethyl)benzonorbornadiene (16) and 6-(trifluoromethyl)benzonorbornadiene (23) by hydroboration-oxidation.The endo alcohols were available from the corresponding exo alcohols by oxidation to the benzonorbornen-2-ones 24 (5-CF3), 25 (6-CF3), 26 (7-CF3), and 27 (8-CF3) followed by diborane reduction.While in the presence of the electron-withdrawing CF3 group the exo alcohols gave predominantly the endo amines, the endo alcohols afforded exclusively the exo amines.