A Convenient One-Pot Synthesis of 4-Substituted 3,5-Bis(alkoxycarbonyl) -4,5-dihydroisoxazole 2-Oxides from Aldehydes and Nitroacetic Esters in a Solid-Liquid Reaction System and Subsequent Deoxygenation
Synthesis of Fused 3a,4-Dihydro-5a,H-benzofuro[3,3a-d]isoxazoles
作者:Kazuho Harada、Eisuke Kaji、Kuniaki Sasaki、Shonosuke Zen
DOI:10.3987/com-95-7044
日期:——
Reaction of 2-isoxazoline-2-oxides (1) with titanium tetrachloride afforded Diels-Alder dimers (3) of 3a,4-dihydro-5a,H-benzofuro[3,3a-d]isoxazoles (2). The stereochemistry of the dimer (3a) was confirmed by X-ray analysis. As an application of the Diels-Alder reaction, several fused 3a,4-dihydro-5a,H-benzofuro[3,3a-d]isoxazoles (5,6, and 7) were synthesized by the reactions of 2 with acetylenic dienophiles.
An One-Pot Synthesis of 5,11-Ethenoisoxazolo[5''',4''':3',4']furo[2'',3'':7',8']naphtho[2',3':4,5]furo[3,4-d]isoxazoles from 2-Isoxazoline-2-oxides
作者:Kazuho Harada、Kuniaki Sasaki、Eisuke Kaji、Shonosuke Zen
DOI:10.3987/com-92-6234
日期:——
4-Aryl-3,5-bis(methoxycarbonyl)-2-isoxazoline-2-oxides were allowed to react with titanium tetrachloride by one-pot synthesis to afford novel fused heterocycles, 5,11 -ethenoisoxazolo[5''',4''':3',4']furo[2'',3'':7',8']-naphtho[2',3':4,5]furo[3,4-d]isoxazoles, which were also formed by stepwise synthesis via Diels-Alder dimerization of 3a,4-dihydro-5a,H-benzofuro[3,3a-d]isoxazoles attainable from the above isoxazoline-2-oxides. The structure determination of the dimer by single crystal X-ray analysis is reported.
A Convenient One-Pot Synthesis of 4-Substituted 3,5-Bis(alkoxycarbonyl) -4,5-dihydroisoxazole 2-Oxides from Aldehydes and Nitroacetic Esters in a Solid-Liquid Reaction System and Subsequent Deoxygenation
4-Substituted 3,5-bis(alkoxycarbonyl)-4,5-dihydroisoxazole 2-oxides are obtained from nitroacetic esters and imines which are prepared from aldehydes and isopropylamine in the presence of molecular sieves. Reduction of the N-oxides with trimethyl phosphite in dioxane gives the corresponding 4,5-dihydroisoxazoles in good yields.
Highly diastereoselective condensation of α-nitro-esters with aldehydes catalyzed by zinc complexes of amino acids
作者:A. Chatterjee、S.C. Jha、N.N. Joshi
DOI:10.1016/s0040-4039(02)01047-x
日期:2002.7
Zinc complexes of amino acids efficiently catalyze the condensation between α-nitro-esters and a variety of aldehydes. An unusual domino reaction sequence leads to the diastereoselective formation of substituted isoxazoline N-oxides in high yields.