1,5-Dipolar Electrocyclizations in Reactions ofα-Thioxo Ketones andα-Thioxo Thioamides with Diazo Compounds
作者:Daniel H. Egli、Anthony Linden、Heinz Heimgartner
DOI:10.1002/hlca.200690182
日期:2006.9
compounds were investigated. Most of them proceeded via a reactive thiocarbonyl ylide, which underwent a [2 + 3] cycloaddition with the α-thioxo ketone to give the ‘Schönberg products’ 17–19 or a 1,5-dipolar electrocyclization to give the corresponding five membered 1,3-oxathioles (i.e., 13, 20a, 20b, 21, and 25) and 1,3-dithioles (i.e., 33, 34, and 35), respectively. In the case of thioamide 32, the
研究了α-硫代酮和α-硫代硫酰胺与重氮化合物的几种反应。它们中的大多数是通过反应性硫代羰基内酯进行的,后者与α-硫代酮进行[2 + 3]环加成反应,得到“ Schönberg产品” 17 – 19或1,5-双极电环化得到相应的五元1 ,3- oxathioles(即,13,20A,20B,21,和25)和1,3- dithioles(即,33,34,和35),分别。在硫代酰胺的情况下32,硫代羰基乙炔经过竞争性的1,3-偶极电环化反应生成相应的噻喃基。在这些情况下,自发脱硫导致相应的烯烃36和37。所使用的硫代羰基或重氮化合物的性质似乎对反应路径起决定性作用。当重氮化合物在重氮基团的β位置带有至少一个H原子时(即重氮环己烷15f),在与α-硫代酮或α-硫代硫代酰胺的反应中,无法分离出任何电环化的产物。在这些情况下,分离出的唯一产物是2-[((环己-1-烯基)硫烷基] -1,2-二苯乙酮(2