Titanium-Mediated Diastereoselective Formation of (E)- or (Z)-2-Substituted 1-Vinylcyclopropanols: Scope and Limitation, Applications

✍ Scribed by Sandrine Racouchot; Isabelle Sylvestre; Jean Ollivier; Yuri Yu. Kozyrkov; Alexei Pukin; Oleg G. Kulinkovich; Jacques Salaün

• Publisher: John Wiley and Sons
• Year: 2002
• Tongue: English
• Weight: 312 KB
• Volume: 2002
• Category: Article
• ISSN: 1434-193X
• DOI: 10.1002/1099-0690(200207)2002:13<2160::aid-ejoc2160>3.0.co;2-1

✦ Synopsis

Titanium-mediated cyclopropanation of α,β-unsaturated esters failed to provide 1-vinylcyclopropanol derivatives in useful yields, but (E)-2-substituted-1-vinylcyclopropanols were formed diastereoselectively from O-protected β-oxo-and βhalo esters, with the allylic double bond being created subsequently (Knoevenagel condensation or dehydrohalogenation). Titanium-mediated cyclopropanation of homoallyl alk-2-enoates, on the other hand, directly provided the corres- [ ‡] In contrast to IUPAC nomenclature rules, the (E)/(Z) descriptors used in this article refer to the relative stereochemistry of the cyclopropane substituents.