Oxidation of spiroketones with DDQ - synthesis of tropone derivatives and DDHQ diesters
作者:Tirumalai R. Kasturi、Palle V.P. Pragnacharyulu、Gouravaram M. Reddy、Srirangam K. Jayaram、Sheo B. Singh
DOI:10.1016/s0040-4020(01)88302-2
日期:1992.1
derivatives 4a–f and DDHQ esters 5a–f (- isomer 6a–f, - isomer 7a–f). While the aryl substituted spirokeone 17a gave a 2:1 mixture of 19a and the corresponding - isomer, the aryl substituted spiroketones 17b–d gave exclusively - isomers 19b–d. Heating acid chloride of acid 9c with DDHQ resulted in compounds 4a and 7a, thus confirming the structures assigned. Mechanism of formation of these compounds
用干苯中的DDQ氧化螺酮3a-f,得到托克酮衍生物4a-f和DDHQ酯5a-f(-异构体6a-f,-异构体7a-f)。而芳基取代spirokeone 17A给予了2:1混合物19A相应的和-异构体,所述芳基取代的spiroketones 17B-d仅仅得到-异构体19B-d 。用DDHQ加热酸9c的酰氯得到化合物4a和7a,从而确认分配的结构。这些化合物的形成机理已经合理化。对化合物7d的2D 1 H- 1 H COSY,1 H- 13 C COSY,HMBC和2D NOESY的详细研究导致1 H和13 C NMR信号及其溶液构象的完全分配。