Alcohol-Assisted Phosphine Catalysis: One-Step Syntheses of Dihydropyrones from Aldehydes and Allenoates
摘要:
This paper describes the phosphine-catalyzed annulation of methyl allenoate with various aromatic aldehydes to form 6-aryl-4-methoxy-5,6-dihydro-2-pyrones. In this reaction, the addition of an alcohol was necessary to induce dihydropyrone formation, with the optimal agent being methanol. Moreover, the addition of n-butyllithium suppressed the formation of the noncyclized product, leading to the exclusive isolation of the dihydropyrone. This method provides an efficient, one-step route toward disubstituted dihydropyrones from simple, stable starting materials.
Alcohol-Assisted Phosphine Catalysis: One-Step Syntheses of Dihydropyrones from Aldehydes and Allenoates
作者:Gardner S. Creech、Ohyun Kwon
DOI:10.1021/ol702462w
日期:2008.2.1
This paper describes the phosphine-catalyzed annulation of methyl allenoate with various aromatic aldehydes to form 6-aryl-4-methoxy-5,6-dihydro-2-pyrones. In this reaction, the addition of an alcohol was necessary to induce dihydropyrone formation, with the optimal agent being methanol. Moreover, the addition of n-butyllithium suppressed the formation of the noncyclized product, leading to the exclusive isolation of the dihydropyrone. This method provides an efficient, one-step route toward disubstituted dihydropyrones from simple, stable starting materials.
Theory-guided design of Brønsted acid-assisted phosphine catalysis: synthesis of dihydropyrones from aldehydes and allenoates
作者:Gardner S. Creech、Xue-Feng Zhu、Branden Fonovic、Travis Dudding、Ohyun Kwon
DOI:10.1016/j.tet.2008.04.075
日期:2008.7
was also found for the first time to be a suitable catalyst for the synthesis of dihydropyrones. This method provides a one-step route toward functionalized dihydropyrones from simple, stable starting materials. In addition, newreaction pathways of phosphine-catalyzed allene annulations are unveiled, with the formation of dihydropyrones being the first example of dual activation in this sphere.