Studien über die Reformatsky‐Reaktion, I

Abstract

Die Reformatsky-Reaktion zwischen Cyclohexenoxyd und Bromessigester wurde erneut untersucht und die Ausbeute an P-Hydroxy-P-cyclopentyl-propionsaure-athylester (I) verbessert. Fur die Ringverengung wird ein Reaktionsmechanismus vorgeschlagen. I spaltet mit Phosphoroxychlorid in Pyridin Wasser ab zum 6-Cyclopentyl-acrylsaureester, der bei der Michael-Addition mit Acetessigester 4-Carbathoxy-5-cyclopentyl-cyclohexandion-(l.3) ergibt. 5-SubstituierteResorcine werden bequem iiber die entsprechenden 5-substituierten Dihydroresorcine (Cyclohexandione-( 1.3)) erhalten, die im allgemeinen entweder durch Michael-Addition eines a-Diesters an ein a.P-ungesattigtes Keton') oder eines P-Ketoesters an einen =.a-ungesattigten Ester % 3 ) und anschlieBende Dieckmann-Cyclisierung der Addukte hergestellt werden.

Synthetic applications of ethyl 3-bromodifluoromethyl-3-benzyloxy-acrylate as a gem-difluorination building-block: Its reactions with aldehyde and epoxide

“…However, the reaction of epoxide with zinc reagents was just reported in few cases [15]. We also examined the epoxide ring opening reaction by the zinc reagent from 1 after the reaction of acrylate 1 with aldehydes was studied.…”

Photoisomerization of some bicyclooctanones in solution

“…Prior to this work the only photochemical study of a bicyclo[3.2.l]octan-2-one was that of homocamphor (12) (14). Irradiation of homocamphor in diethyl ether containing cyclohexylamine had afforded only the ketene derived product (as the amide) and no aldehyde was detected.…”

“…This material was identified as dimethyl 4-carbomethoxyheptane-1,7-dioate (11) (13) (12) in absolute methanol (3.5 ml) containing sodium bicarbonate (0.010 g) was irradiated for 7 h. After evaporation of the solvent and the addition of petroleum ether, the solution was filtered and concentrated to yield a colourless oil (0.054 g, 9973, shown by glc analysis (column A, 187°C) to be a mixture of two new components (ratio 4: 1) in addition to 12 (-10%). The aldehyde-ester ratio of 4: 1 was confirmed by the 'Hmr spectrum (CCI,): 3.60 (s, OCH,), 9.67 (t, J 1.5 Hz, CHO) ppm.…”

“…Isolation of ( ) -Homocamphor (12) To a 1 : 1 mixture of (&)-homo-and (+)-homoepicamphor (1.01 g, 0.006 mol) obtained by ring expansion of (&)-camphorquinone (24) followed by reduction (24) was added aqueous semicarbazide hydrochloride solution (1.5 ml, 0.5 mol equiv.) and enough methanol (-3 ml) to produce a clear solution.…”