Cycloaddition of 1-Methyl-2(1<i>H</i>)-Quinolones Having an Electron-Withdrawing Group at the 3 or 4-Position with 1,3-Butadiene Derivatives

Abstract

Cycloaddition of 1 methyl 2(1H ) quinolones with electron-withdrawing groups such as methoxycarbonyl, cyano, and acetyl groups, at the 3 or 4 position with 2,3 dimethoxyand 2 (trimethylsilyloxy) 1,3 butadienes aŠorded stereoselectively phenanthridone derivatives under atmospheric and high pressures. Furthermore, regioselectivities of the cycloaddition of 3or 4 substituted 2(1H ) quinolones with 2 (trimethylsilyloxy) 1,3 butadiene were examined using MO calculation.Key words-4 cyano 2(1H ) quinolone; 2,3 dimethoxy 1,3 butadiene; cycloaddition; regioselectivity; stereoselectivity180°C で 3 日間加熱すると，立体選択的に cis 付加 体（3a, 25％; 3b, 30％;

Cycloadditions of 1-Substituted 1,3-Butadienes with 4- or 3-Substituted 2(1H)-Quinolones Acting as Dienophiles.

“…1). [13][14][15][16] Signals due to H-6a in 9a-g and 10a-f appeared at d 3.10-3.82. These results confirmed cis stereochemistry in the ring junctures of 9a-g, and 10a-f.…”

“…[10][11][12] We recently reported phenanthridine synthesis by cycloaddition of 1-methyl-2(1H)-quinolones having an electron-withdrawing group at the 4-or 3-position that acts as a dienophlie towards 2-, 2,3-substituted dienes as well as Danishefsky's diene. [13][14][15][16] However, there are no reports regarding cycloaddition of 1-substituted 1,3-butadienes with 1-methyl-2(1H)-quinolones. Herein, we report the synthesis of phenanthridines richly functionalized by cycloaddition of 1,3-butadienes bearing methoxy or equivalent groups at the 1-or 1,4-positions with 1-methyl-2(1H)-quinolones under atmospheric and high pressure (AP and HP) conditions, and we investigate of the reactivity of the 2(1H)-quinolones using MO calculation.…”

“…Cycloaddition of 7 with 1 at 160 and 180°C gave only a single cis-endo-adduct (9e, 30%; entry 11 and 9e, 30%; entry 12), whereas cycloaddition of 7 with 2 (entries 13,14) afforded several cis-endo-adduct (9f, 3%, 7%) and cis-exo-adduct (10f, 11%, 12%). Reaction of 8 with 1 (entries 15,16) proceeded to stereoselectively afford cisendo-adduct (9g, 38%, 10%, respectively). Cycloaddition of 1-methoxydiene 5 with quinolone 3 having a methoxycarbonyl group at the 3-position at 180 and 160°C for 6 d (entries 17,18) was then performed and gave cis-endo-adducts (11a, 14%, 3%) and (12a, 11%, 14%), respectively.…”