Conjugate propargylation of α,β-unsaturated lactones: a solution via 1,4-addition of (Z)-2-ethoxyvinyl anion
摘要:
Conjugate addition of (Z)-2-ethoxyvinyl anion to alpha,beta -unsaturated lactones is best effected via Noyori-type organocopper reagents. The resulting adducts may be advanced to beta -propargyllactones or utilized in the preparation of functionalized pyridines. (C) 2000 Elsevier Science Ltd. All rights reserved.
Die α‐Methylen‐γ‐butyrolactone 1‐28 wurden auf molluskizide Wirkung gegen Biomphalaria glabrata untersucht. Die racem. Verbindung 25 ist am wirksamsten. Die Synthese erfolgte durch modifizierte Reformatzky‐Reaktion aus den entspr. Carbonylverbindungen und Brommethylacrylsäureethylester. 7‐10, 17 und 22‐27 wurden erstmalig synthetisiert.
The electroreduction of a catalytic amount of ZnBr2 in acetonitrile provided a active Zn*, able to catalyze the reductive coupling of allyl bromides and chlorides with carbonyl compounds with high regioselectivity. Substituted α-methylene γ-lactones were obtained from functionalized allyl derivatives.
Thirty-five alpha-methylene-gamma-butyrolactones have been prepared and their allergenic properties tested on the skin of guinea pigs experimentally sensitized to (a) alantolactone (1), (b) isoalantolactone (2), and (c) alpha-methylene-gamma-butyrolactone (3). The two first groups of animals cross-react to lactones containing 9 to 18 carbon atoms but not to smaller alpha-methylene-gamma-butyrolactones. Conversely, animals sensitized to alpha-methylene-gamma-butyrolactone react only with alpha-methylene-gamma-butyrolactones containing 6 and 7 carbon atoms. These results are discussed in relation with the allergic contact dermatitis mechanism.
Reductive cyclization of 2-[(2-propynyl)oxy]ethyl bromides by a cobalt complex, cobaloxime(I). A new method for the synthesis of .alpha.-methylene-.gamma.-butyrolactones
作者:Masami Okabe、Masayoshi Abe、Masaru Tada
DOI:10.1021/jo00348a040
日期:1982.4
FITT J. J.; GSCHWEND H. W., J. ORG. CHEM., 1980, 45, NO 21, 4257-4959