Studies on telomers and oligomers of vinylene carbonate. VI. Stereoselective conversion of vinylene carbonate telomers to trans unsaturated phosphate esters and their chemical behaviors.
作者:NAOKI MITSUO、TAKEHISA KUNIEDA、TAKEO TAKIZAWA
DOI:10.1248/cpb.25.231
日期:——
Smooth conversion of telomers of vinylene carbonate with carbon tetrachloride or methylene bromide as a telogen to novel trans enol phosphates, and the reactivities of the phosphates thus formed are described. Both trans-"anti"-trans- and trans-"syn"-trans-isomers of the n=2 telomers, 5-chloro-5'-trichloromethyl-(4, 4'-bi-1, 3-dioxolan)-2, 2'-dione and 5-bromo-5'-dibromomethyl-(4, 4'-bi-1, 3-dioxolan)-2, 2'-dione gave, on treatment with trialkyl phosphites, the identical trans dialkyl 2-(5-trichloromethyl- and 2-(5-dibromomethyl-2-oxo-1, 3-dioxolan-4-yl) vinyl phosphates in good yields, without any detectable amount of cis isomer and the phosphonate, while the n=1 adduct failed to give the corresponding enol phosphate. Stereospecific conversion of the phosphate to cis 2-(5-trichloromethyl-2-oxo-1, 3-dioxolan-4-yl) vinyl acetate was readily achieved by new vinylic exchange reaction catalyzed by palladium chloride in acetic acid by way of the processes, trans oxypalladation and trans deoxypalladation. Reactions involving catalytic hydrogenation, chlorination with titanium chloride and conversion to α, β-unsaturated aldehydes are summarized in Chart 2.
介绍了
碳酸亚乙烯酯的端聚物与
四氯化碳或
溴化亚甲基作为端聚物顺利转化为新型反式烯醇
膦酸盐,以及由此形成的
膦酸盐的反应活性。反"-反式-反式异构体和反 "同"-反式-反式异构体的 n=2 端粒,5-
氯-5'-三
氯甲基-(4,4'-联-1,3-二
氧戊环)-2,2'-二酮和 5-
溴-5'-二
溴甲基-(4,4'-联-1,3-二
氧戊环)-2,2'-二酮,经三烷基
亚磷酸盐处理后,产生了相同的反式二烷基 2-(4,4'-联-1,3-二
氧戊环)-2,2'-二酮、2-(5-三
氯甲基-和 2-(5-二
溴甲基-2-氧代-1,3-二
氧戊环-4-基)
乙烯基膦酸盐的相同的反式二烷基,收率很高,没有检测到任何数量的顺式异构体和
膦酸盐,而 n=1 加合物未能得到相应的烯醇
磷酸酯。在
氯化钯的催化下,在
乙酸中通过反式
氧化钯化和反式脱氧
钯化反应,很容易将
磷酸酯立体特异性地转化为顺式 2-(5-三
氯甲基-2-氧代-1, 3-二
氧戊环-4-基)
乙烯基乙酸酯。涉及催化加氢、
氯化
钛氯化和转化为 α、β-不饱和醛的反应见图 2。