Regioselective and stereospecific acylation across oxirane- and silyloxy systems as a novel strategy to the synthesis of enantiomerically pure mono-, di- and triglycerides
作者:Stephan D. Stamatov、Jacek Stawinski
DOI:10.1039/b713246h
日期:——
acyl residue at the central carbon of the silylated synthons with a subsequent Et(3)N.3HF-promoted, direct trichloroacetylation across the siloxy system by trichloroacetic anhydride (TCAA), followed by cleavage of the trichloroacetyl group, affords the respective 1,2(2,3)-diacyl- or 1(3)-O-alkyl-2-acyl-sn-glycerols. Alternatively, a reaction sequence involving: (i) attachment of a trichloroacetyl fragment
三氟乙酸催化带有三氟乙酸酐(TFAA)的带有烯丙基酰基或烷基官能团的缩水甘油基衍生物的环氧乙烷环的开环,可有效进入构型均质的1(3)-酰基-或1(3)-O-烷基-sn -甘油。在这些关键中间体的末端位置选择性引入叔丁基二甲基甲硅烷基-(TBDMS)或三异丙基甲硅烷基-(TIPS)瞬态保护可确保1(3)-酰基-或1(3)-O-烷基-3(1)- O-TBDMS(或TIPS)-sn-甘油作为1,2(2,3)-二酰基-,1(3)-O-烷基-2-酰基-和1,3-二酰基-sn-的一般双功能前体甘油和三酯等排体。通过三氯乙酸酐(TCAA)在甲硅烷基化的合成子的中央碳原子上引入必要的酰基残基,并随后进行Et(3)N.3HF促进的,直接的三氯乙酰化作用穿过硅烷氧基体系 然后裂解三氯乙酰基,得到各自的1,2(2,3)-二酰基-或1(3)-O-烷基-2-酰基-sn-甘油。可选择地,反应序列包括:(i)三氯乙酰基片段连接在单甲硅烷基化甘油酯的立体C