Reactions of Polycyclic Ketones with Dimethoxycarbene; a Convenient Route for a ‘One-Pot’ Preparation of Someα-Hydroxycarboxylic Acid Esters
作者:Jarosław Romański、Grzegorz Mlostoń、Heinz Heimgartner
DOI:10.1002/hlca.200790128
日期:2007.7
nucleophilic dimethoxycarbene (DMC; 1), which was generated thermally from 2,5-dihydro-2,2-dimethoxy-5,5-dimethyl-1,3,4-oxadiazole (4a) in boiling toluene. In this ‘one-pot’ procedure, the α-hydroxycarboxylic acid ester 12 or a corresponding derivative 15 or 17 was obtained (Schemes 4–7). Additionally, ‘cage’ thione 21 was treated with DMC under the same conditions yielding dimethoxythiirane 22 (Scheme 8). Subsequent
多环“笼”酮,例如五环[5.4.0.0 2,6 .0 3,10 .0 5,9 ]十一碳八一(10),五环[5.4.0.0 2,6 .0 3,10。将0,9 ]十一烷-8,11-二酮(11)和金刚烷-2-酮(16)用亲核性二甲氧基卡宾(DMC; 1)处理,该亲核性二甲氧基卡宾是由2,5-二氢-2生成的,在沸腾的甲苯中的2-二甲氧基-5,5-二甲基-1,3,4-恶二唑(4a)。在该“一锅法”程序中,α-羟基羧酸酯12或相应的衍生物15或17已获得(方案4–7)。另外,在相同条件下用DMC处理“笼”硫酮21,得到二甲氧基硫代乙烷22(方案8)。的随后的水解或脱硫(随后水解经硅胶)22,得到α -mercaptocarboxylate 25和相应的脱硫酯24分别。在所有情况下,DMC的添加都是立体选择性地发生的,并且假定从exo- face进行的添加可以解释分离产物的结构。