| Title | Spiroborate Ester-Mediated Asymmetric Synthesis of beta-Hydroxy Ethers and Its Conversion to Highly Enantiopure beta-Amino Ethers. | | Author(s) | Huang K, Ortiz-Marciales M, Correa W, Pomales E, López XY | | Institution | Department of Chemistry, University of Puerto RicoHumacao, CUH Station, Humacao, Puerto Rico 00791-4300. | | Source | J Org Chem 2009 May 4. | | Abstract | Borane-mediated reduction of aryl and alkyl ketones with alpha-aryl- and alpha-pyridyloxy groups affords beta-hydroxy ethers in high enantiomeric purity (up to 99% ee) and in good yield, using as catalyst 10 mol % of spiroborate ester 1 derived from (S)-diphenylprolinol. Representative beta-hydroxy ethers are successfully converted to beta-amino ethers, with minor epimerization, by phthalimide substitution under Mitsunobu's conditions followed by hydrazinolysis to obtain primary amino ethers or by imide reduction with borane to afford beta-2,3-dihydro-1H-isoindol ethers. Nonracemic Mexiletine and nAChR analogues with potential biological activity are also synthesized in excellent yield by mesylation of key beta-hydroxy pyridylethers and substitution with five-, six-, and seven-membered ring heterocyclic amines. | | Language | ENG | | Pub Type(s) | JOURNAL ARTICLE
| | PubMed ID | 19413288 |
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