Stereoselective radical cyclizations of N-(2-halobenzoyl)-cyclic ketene-N,X(X=O, S)-acetals
作者:Aihua Zhou、Moses N. Njogu、Charles U. Pittman
DOI:10.1016/j.tet.2006.02.018
日期:2006.4
2-Alkyloxazolines and 2-alkylthiazolines react with 2-halobenzoyl chlorides to form N-(2-halobenzoyl)-cyclic ketene-N,O-acetals and N-(2-halobenzoyl)-cyclic ketene-N,S-acetals in excellent yields, respectively. These ketene acetals readily undergo stereocontrolled aryl radical cyclizations to afford the central six-membered rings of substituted-2,3,10,10α-tetrahydrooxazolo[3,2-b]isoquinolin-5-ones
2-烷基恶唑啉和2-烷基噻唑啉与2-卤代苯甲酰氯反应生成N-(2-卤代苯甲酰基)-环烯酮-N,O-缩醛和N-(2-卤代苯甲酰基)-环烯酮-N,S-缩醛产量分别。这些乙烯酮缩醛易于进行立体控制的芳基自由基环化,以提供取代的2,3,10,10α-四氢恶唑并[3,2 - b ]异喹啉-5-酮及其2,3,10,10α的中心六元环-四氢噻唑并[3,2 - b ]异喹啉-5-酮类似物。第三级N,O-和N,S-在烯酮-N,X(X = O,S)-乙缩醛双键上发生的由芳基自由基反应形成的基团似乎具有合理的稳定性。研究了这些中间自由基从Bu 3 SnH和(Me 3 Si)3 SiH提取氢的立体选择性。的Ñ,š -杂环稠环的产品可能具有潜在的医疗价值。