Chain Extension of Boronic Esters with Lithiooxiranes Generated by Sulfoxide-Metal Exchange - Stereocontrolled Access to 2°/2°, 2°/3°, and 3°/3° Vicinal Diols and Related Compounds
作者:Embarek Alwedi、Lev N. Zakharov、Paul R. Blakemore
DOI:10.1002/ejoc.201403105
日期:2014.10
β-silyloxyboronates that were converted to vicinal diol monosilyl ethers by oxidative work-up with aq. NaOOH. The 2°/2° (4–32 %, dr > 98:2), 2°/3° (21–66 %, dr ≥ 65:35), and 3°/3° (59–68 %, dr ≥ 95:5) contiguous stereodiad-containing compounds created in this manner were typically obtained in a highly stereocontrolled manner. In general, cis-sulfinyl epoxides afforded anti-like stereodiads, whereas trans-sulfinyl
环氧乙烷 [LiCR1(O)CR2R3, R1 = H, Me; R2/R3 = H/Ph、H/tBu、Me/Ph],由立体定义的亚磺酰基环氧化物(使用 PhLi 或 tBuLi、THF,在 –90 °C 或以下)通过亚砜-锂交换生成,用于硼酸酯 R0–Bpin(R0 = BnCH2、烯丙基、cHex、Ph)的立体特异性试剂控制同源性。将 TBSOTf 添加到中间体 ate 络合物中得到 β-甲硅烷氧基硼酸酯,通过水溶液氧化处理将其转化为邻二醇单甲硅烷基醚。氢氧化钠。2°/2°(4–32 %,dr > 98:2)、2°/3°(21–66 %,dr ≥ 65:35)和 3°/3°(59–68 %,dr ≥ 95:5) 以这种方式产生的连续含有立体二元组的化合物通常以高度立体控制的方式获得。一般来说,顺式亚磺酰基环氧化物提供抗样立体二联体,而反式亚磺酰基环氧化物提供顺式立体二联体;然而,