PBu<sub>3</sub>-Mediated Vinylogous Wittig Reaction of α-Methyl Allenoates with Aldehydes and Mechanistic Investigations
作者:Silong Xu、Rongshun Chen、Zhengjie He
DOI:10.1021/jo201466k
日期:2011.9.16
A highly stereoselective PBu3-mediated vinylogous Wittigolefination between α-methyl allenoates and a variety of aldehydes is presented as the first example of a practical and synthetically useful vinylogous Wittig reaction. Mechanistic experiments including deuterium-labeling, intermediate entrapment, and NMR monitoring have been deliberately conducted. On the basis of mechanistic investigations
Phosphine-Catalyzed β′-Umpolung Addition of Nucleophiles to Activated α-Alkyl Allenes
作者:Tioga J. Martin、Venus G. Vakhshori、Yang S. Tran、Ohyun Kwon
DOI:10.1021/ol200697m
日期:2011.5.20
Highly function alized alkenes can be prepared through phosphine-catalyzed beta'-umpolung additions of nucleophiles (carbon-, oxygen-, nitrogen-, and sulfur-centered) to activated alpha-disubstituted allenes, providing many potentially useful synthetic intermediates in good to excellent yields, often with high levels of stereoselectivity for the product olefin geometry. Various substitution patterns around the allene are compatible with the process, showcasing the synthetic utility of allenes under the conditions of nucleophilic phosphine catalysis.
Navarro Charles, Degueil-Castaing Marie, Colombani Daniel, Maillard Berna+, Synth. Commun., 23 (1993) N 7, S 1025-1037