Regio- and Stereoselectivity in theLewis Acid- and NaH-Induced Reactions of Thiocamphor with (R)-2-Vinyloxirane
作者:Alexey Fedorov、Changchun Fu、Heinz Heimgartner
DOI:10.1002/hlca.200690046
日期:2006.3
The reaction of the enolizable thioketone (1R,4R)-thiocamphor (= (1R,4R)-1,7,7-trimethylbicyclo[2.2.1]heptane-2-thione; 1) with (R)-2-vinyloxirane (2) in the presence of a Lewis acid such as SnCl4 or SiO2 in anhydrous CH2Cl2 gave the spirocyclic 1,3-oxathiolane 3 with the vinyl group at C(4′), as well as the isomeric enesulfanyl alcohol 4. In the case of SnCl4, an allylic alcohol 5 was obtained in
可烯化的硫酮(1 R,4 R)-硫樟基(=(1 R,4 R)-1,7,7-三甲基双环[2.2.1]庚烷-2-硫酮; 1)与(R)- 2-乙烯基环氧乙烷(2在存在下)一个路易斯酸如的SnCl 4或SiO 2在无水CH 2氯2,得到螺环-1,3-氧硫杂环戊烷3与C(4')中的乙烯基基团,以及所述异构体亚烷基硫醇4。在SnCl 4的情况下,除了低收率之外,还以低收率获得了烯丙醇5。图3和图4(方案2)。在ZnCl 2的存在下重复反应,得到两个非对映异构的4-乙烯基-1,3-氧杂硫杂环戊烷3和7以及醇4和'1:2加合物' 8(方案3)。反应1和2在NaH存在区域选择性2 enesulfanyl醇,得到4和9,其中,在CDCl 3,环化顺利,得到相应的螺环-1,3-氧硫杂环戊烷3,10,和11分别(方案4)。在HCl的存在下,发生3和10的差向异构体分别产生相应的差向异构体7和11(方案5)。沸腾的