Holt David J, Barker William D, Ghosh Subrata, Jenkins Paul R
Department of Chemistry, The University of Leicester, Leicester, UK LE1 7RH.
Org Biomol Chem. 2004 Apr 7;2(7):1093-7. doi: 10.1039/b315623k. Epub 2004 Feb 25.
Intramolecular [2 + 2] photoannulation catalysed by copper(i)triflate has been applied to a series of carbohydrate derivatives obtained from glucose. Dienes 1a and 1b lead to cyclobutanes 3a and 3b whereas the diastereoisomeric dienes 5a and 5b gave diastereoisomeric products 7a and 7b. These results demonstrate that the reaction is stereospecific. Products 3a and 7a were converted into bromoesters 4 and 9 respectively. The Vasella elimination of 8 lead to the expected bicyclic aldehyde 10 and the ring expanded hydroxy ketone 12. The stereospecific formation of enantiomerically pure spiro annulated carbohydrates 18a and 18b was demonstrated whereas in example 19 no selectivity in the formation of 20 and 21 was observed.
由三氟甲磺酸铜（I）催化的分子内[2 + 2]光环化反应已应用于一系列从葡萄糖获得的碳水化合物衍生物。二烯1a和1b生成环丁烷3a和3b，而非对映异构二烯5a和5b则生成非对映异构产物7a和7b。这些结果表明该反应具有立体专一性。产物3a和7a分别转化为溴代酯4和9。8的瓦塞拉消除反应生成预期的双环醛10和扩环羟基酮12。对映体纯的螺环化碳水化合物18a和18b的立体专一性形成得到了证实，而在实例19中，未观察到20和21形成过程中的选择性。
