Regio- and stereoretentive synthesis of branched, linear (E)- and (Z)-allyl fluorides from allyl carbonates under Ir-catalysis
作者:Elena Benedetto、Matthew Tredwell、Charlotte Hollingworth、Tanatorn Khotavivattana、John M. Brown、Véronique Gouverneur
DOI:10.1039/c2sc21789a
日期:——
This paper describes a new catalytic method for the regio- and stereocontrolled fluorination of allylic carbonates. This transformation uses TBAF·4tBuOH as the fluoride source and [Ir(COD)Cl]2 as the catalyst; the most commonly used [Ir(COD)Cl]2/phosphoramidite system is ineffective. Synthetically, this reaction is characterized by a high degree of structural conservation in going from substrates to the products. The fluorination of (E)-allylic carbonates leading to linear (E)-allylic fluorides (l : b > 20 : 1, E : Z > 20 : 1) is unprecedented and a unique feature of fluoride as the nucleophile. The first examples of transition metal catalyzed fluorination affording (Z)-allyl fluorides (Z : E ratio >20 : 1) are disclosed along with the successful fluorination of branched, linear (E)- and (Z)-allyl carbonates with [18F] fluoride in the presence of [Ir(COD)Cl]2. 18O-Labeling of the reactant reveals internal return during the allylic ionization step, and pathways for effective intra- and intermolecular isotope exchange.
Process for preparing ethylene interpolymers and ethylene interpolymers obtained therefrom
申请人:WESTLAKE LONGVIEW CORPORATION
公开号:EP1195393B1
公开(公告)日:2010-04-07
US5250743A
申请人:——
公开号:US5250743A
公开(公告)日:1993-10-05
Ru-Catalyzed Chemoselective Olefin Migration Reaction of Cyclic Allylic Acetals to Enol Acetals
作者:Kyeongdeok Seo、Ye ji Kim、Young Ho Rhee
DOI:10.1021/acs.orglett.7b03900
日期:2018.2.16
A Ru-catalyzed olefin migration reaction of chiral cyclic allylic acetal is reported. The reaction generates cyclic enol acetal in a highly chemoselective manner. A variety of O,O- and N,O-acetals participated in the reaction with conservation of the stereochemical integrity of the acetal moiety. The utility of the reaction was demonstrated by the short and protective group-free syntheses of (L)-deoxyribonucleoside