Cleavage of Acetals Promoted by Copper (II) Sulphate Adsorbed on Silica Gel
摘要:
Copper sulphate supported on silica gel promotes the easy removal of cyclic acetals and tetrahydropyranyl ethers to give the respective parent carbonyl and hydroxyl compounds.
已经制备了具有二甲基苯基甲硅烷氧基(DPSO)基团和另外的C3和/或C17酮官能团的类固醇。DPSO基团已用于收获266 nm光子,然后通过分子内单重态-单重态能量转移(Intra-SSET)激活酮功能。因此,单酮3,3-(亚乙二氧基)-6beta-(DPSO)-5beta-雄烷-17-1(6)和6beta-(DPSO)-5beta-雄烷-3-1(8)均显示DPSO引发的羰基上的光化学。辐照二酮6beta-(DPSO)-5beta-androstane-3,17-dione(5),得到两个D环衍生的光产物,一个差向异构体(19)和一个烯醛(18),它们都来自C17酮。兴奋的单重态。在这里,从芳基天线到羰基的Phi(in-SSET)约为。88%的效率,发生率约为 6.5 x 10(9)s(-)(1),化学指示C3和C17酮之间的内部SSET容易。C3处的亚烷基(例如,如6beta-(DPSO
1,3-Disubstituted tetrabutyldistannoxanes catalyze acetilization of carbonyl compounds undermildconditions. Thorough investigations of factors influencing this reaction are given. A variety of synthetically useful carbonyl compounds are efficiently converted to acetals. In particular, acetilization of cyclic α,β-unsaturated ketones is readily achieved which have met with only limited success so far