Synthesis and Reactivity of Optically Active Spiroketals by Ring-Expansion of Chromium Carbene Complex-Derived Cyclobutanones
作者:Ana B. Bueno、Louis S. Hegedus
DOI:10.1021/jo971665v
日期:1998.2.1
Photolysis of cyclic chromium alkoxycarbene complexes with an optically active ene-carbamate gave spirofused, optically active cyclobutanones. Baeyer-Villiger ring expansion followed by further functionalization gave optically active spiroketals. Photochemical ring expansion of these spirofused cyclobutanones in the presence of acetic acid or thiophenol gave 2-acetoxy- or 2-(thiophenoxy)-4-spirofused
环状铬烷氧基卡宾配合物与旋光烯-氨基甲酸酯的光解得到螺合的旋光环丁酮。Baeyer-Villiger扩环,然后进一步官能化,得到旋光螺帽。这些螺旋稠合的环丁酮在乙酸或苯硫酚存在下的光化学环扩环得到2-乙酰氧基-或2-(硫代苯氧基)-4-螺合的四氢呋喃。消除噻吩氧基基团得到3,4-二氢呋喃,其经过Heck芳基化和与铬卡宾络合物的光化学环加成反应得到环丁酮。