Simple enols. 1. The generation of vinyl alcohol in solution and its detection and characterization by NMR spectroscopy
作者:Brian Capon、David S. Rycroft、Thomas W. Watson、Cesar Zucco
DOI:10.1021/ja00397a029
日期:1981.4
|4J(HOCβHsyn)| < 0.2 Hz. Under the conditions used vinyl alcohol was converted into acetaldehyde ca 100 times faster than ethyl vinyl ether but could nevertheless be kept in solution for several hours below ca −10 °C. The postulated intermediate, methyl vinyl hemiorthoformate, could not be detected in the hydrolysis of 1, 3, and 4 nor could methyl vinyl hemiorthoacetate be detected in the hydrolysis of
通过水解甲氧基(乙烯基氧基)甲基氯乙酸酯和乙酸酯(1 和 3)、双(乙烯基氧基)甲基二氯乙酸酯和三氯乙酸酯(7 和 6)、原甲酸乙烯酯二甲酯(4)、原乙酸乙烯酯二甲酯(5),已生成乙烯醇, [2H3]乙腈水溶液或[2H7]二甲基甲酰胺水溶液中的乙烯酮甲基乙烯基乙缩醛(8)。通过 1H 和 13C NMR 光谱和转化为乙醛对其进行表征。在用 OD 替换 OH 时,13C NMR 谱显示在对乙基乙烯基醚的相应碳检测不到此类位移的条件下,α-和 β-碳的同位素位移为 -0.12 和 -0.09 ppm。具有 OH 基团的乙烯醇在-10 °C 下以 8 作为前体在 CD3COCD3 (99 v %)/H2O (1 v %) 中缓慢羟基-质子交换的条件下生成,并评估了以下偶联常数:3Jtrans = +14.0, 3Jcis = +6.3, 2Jgem = -0.8, 3J(HOCαH) = +9.8