Chiral Synthesis via Organoboranes. 18. Selective Reductions. 43. Diisopinocampheylchloroborane as an Excellent Chiral Reducing Reagent for the Synthesis of Halo Alcohols of High Enantiomeric Purity. A Highly Enantioselective Synthesis of Both Optical Isomers of Tomoxetine, Fluoxetine, a

Article abstract of DOI:10.1021/jo00248a005

Diisopinocampheylchloroborane, ^dIpc2BCl, reduces ring and chain sustituted haloaralkyl ketones to the corresponding halo alcohols in excellent enantiomeric excess.In certain cases these alcohols can be upgraded by simple methods to essentially 100percent ee.For instance, (+)- or (-)-3-chloro-1-phenyl-1-propanol is initially obtained in 97percent ee.Simple recrystallisation then furnishes the pure enantiomers.These chiral halo alcohols are highly versatile intermediates.They can be readily cyclized to oxiranes and 2-substituted tetrahydrofurans with retention of chirality.Utilizing this methodology, we have developed an efficient, highly enantioselective synthesis of both optical isomers of the antidepressant drugs, Tomoxetine, Fluoxetine, and Nisoxetine, from the common intermediates (+)-or (-)-3-chloro-1-phenyl-1-propanol.