Doubly Vinylogous Aldol Reaction of Furoate Esters with Aldehydes and Ketones
作者:William T. Hartwig、Tarek Sammakia
DOI:10.1021/acs.joc.6b02473
日期:2017.1.6
The use of bulky Lewis acids, aluminum tris(2,6-diphenylphenoxide) (ATPH) and aluminum tris(2,6-di-2-naphthylphenoxide) (ATNP), in the doubly vinylogous aldol reaction between methyl-5-methyl-2-furoate and aldehydes or ketones is described. These reactions proceed smoothly and in high yields with both enolizable and non-enolizable substrates. This C–C bond-forming reaction enables a new bond construction
Regioselective and stereoselective synthesis of tetrahydrofurans from a functionalized allylic silane and an aldehyde via formal [3+2]-cycloaddition reaction
作者:Steven R. Angle、Inchang Choi
DOI:10.1016/j.tetlet.2008.08.046
日期:2008.10
Allylsilanes are known as useful reagents for the stereoselective formation of ring systems. Previous studies have shown that tetrahydrofurans can be constructed via formal [3+2]-cycloadditions of aldehydes and allylsilanes. A new challenge is to understand the intermediate, after a nucleophile attacks a carbonyl activated by the Lewis acid, in which two silyl-protected alkoxy groups with chemical
Stereoselective Synthesis of Tetrahydrofurans via Formal [3+2]-Cycloaddition of Aldehydes and Allylsilanes. Formal Total Synthesis of the Muscarine Alkaloids (−)-Allomuscarine and (+)-Epimuscarine
作者:Steven R. Angle、Nahla A. El-Said
DOI:10.1021/ja012193b
日期:2002.4.1
The stereoselectivesynthesis of tetrahydrofurans was achieved by formal [3+2]-cycloaddition of allyl and crotylsilanes with alpha-triethylsilyloxy aldehydes. The scope of the reaction was examined by using different alpha-substituted aldehydes and different substituents on the silicon. Tamao oxidation of the products resulted in formation of diols that are easily functionalized allowing an entry to
Stereoselective Synthesis of 3-Alkyl-2-aryltetrahydrofuran-4-ols: Total Synthesis of (±)-Paulownin
作者:Steven R. Angle、Inchang Choi、Fook S. Tham
DOI:10.1021/jo800901r
日期:2008.8.1
[GRAPHICS]A formal [3 + 2]-cycloaddition involving the Lewis acid mediated reaction of alpha-silyloxy aldehydes and styrenes to afford 3-alkyl-2-aryltetrahydrofuran-4-ols has been developed. This methodology was applied to the total synthesis of the naturally occurring furofuran lignan (+/-)-paulownin.
Stereoselective Synthesis of Tetrahydropyrans via a Formal [4 + 2]-Cycloaddition of Allylsilanes