ChemInform Abstract: A Novel Synthesis of Haloalkenes from Aldehydes with Carbon‐Carbon Coupling.

Abstract

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

One‐Pot l‐Proline‐Mediated Stereoselective α‐C(sp2)–H Fluorination of α,β‐Unsaturated Aldehydes through Methoxyfluorination–Elimination

“…In most syntheses, 2‐fluoropropenol is obtained by the reduction of the corresponding ester, synthesized by Wittig, thia‐Wittig, Horner–Wadsworth–Emmons, Peterson, Julia, or deacylative‐olefination reactions, with a strong reducing agent such as DIBAL‐H. The corresponding 2‐fluoropropenal is obtained by mild oxidation of the corresponding alcohol.…”

Regioselective Synthesis of α‐Fluorinated Cyclopentenones by Organocatalytic Difluorocyclopropanation and Fluorine‐Directed and Fluorine‐Activated Nazarov Cyclization

“…Divinyl ketones 7 d , ( Z )‐ 7 e , and ( E )‐ 7 e bearing an alkyl substituent (i.e., isopropyl or butyl group) on the fluoroalkene moiety readily underwent cyclization on increasing the loading of the Lewis acid to afford 13 d (88 % yield; Table , entry 4) and 13 e (79 and 70 % yields; Table , entries 5 and 6), respectively. The Nazarov cyclization of cyclohexenyl ketone 7 i allowed the construction of a bicyclic structure, and led to 13 i in 79 % yield (Table , entry 7).…”

“…The effect of fluoro substituents on the reactivity and selectivity of the Nazarov cyclization was experimentally investigated by using fluorinated ( 7 j , X=F, Scheme ) and fluorine‐free ( 14 , X=H) substrates. A competition experiment demonstrated the rate‐enhancing effect of the fluoro substituent.…”