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Stereoselective Synthesis of Enantiomerically Pure β‐Fluoroalkyl γ‐Butyrolactones by Sulfoxide‐Directed Lactonization
Author(s) -
Bravo Pierfrancesco,
Ar Alberto,
Bandiera Paola,
Bruché Luca,
Ohashi Yuji,
Ono Taizo,
Sekine Akiko,
Zanda Matteo
Publication year - 1999
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/(sici)1099-0690(199901)1999:1<111::aid-ejoc111>3.0.co;2-5
Subject(s) - sulfoxide , chemistry , stereoselectivity , enantiomer , stereochemistry , organic chemistry , catalysis
Enantiomerically pure α,α‐dichloro β‐fluoroalkyl γ‐ p ‐tolylthio γ‐butyrolactones trans ‐ 6a–c have been obtained with excellent stereocontrol (> 98:2) and enantiomeric purity (> 98:2) by sulfoxide‐directed lactonization (Marino's annu‐lation reaction) of β‐fluoroalkyl vinyl sulfoxides ( R )‐( E )‐ 5a–c with dichloroketene. Highly chemoselective dechlorination and desulfurization reactions performed on trans ‐ 6c efficiently provided the β‐chlorodifluoromethyl γ‐butyrolactone ( S )‐ 8c , the absolute stereochemistry of which was determined by X‐ray diffraction analysis of its γ‐ p ‐tolylthio precursor (2 R ,3 S )‐ 7c .