在不同的条件下，烯烃双羟基化可以得到顺式和反式邻二羟基化合物。顺式双羟基化常 用试剂为高锰酸钾，四氧化锇及碘-湿乙酸银。反式羟基化常用的方法是过氧酸法， 另外，Provost 反应也常用。 

1、顺式羟基化 

      在烯烃全羟基化中用高锰酸钾氧化烯烃是应用较广泛的方法。在此氧化反应中，仔细到控制反应条件是非常重要的，否则常发生进一步氧化反应。常规的反应条件是：用水或 含水有机溶剂（丙酮、乙醇或叔丁醇）做溶剂，加计算量低浓度（1%~3%）的高锰酸钾， 在碱性条件下（12 以上），低温反应。在这样的条件下，常可以得到满意的结果。由于不饱和酸在碱性溶液中溶解，所以本法对不饱和酸的全羟基化为合适，收率也高，如 油酸的全羟基化的收率达 80%。 

其反应机理如下： 

     对于不溶于水的烯烃，用高锰酸钾做氧化剂时，加入相转移催化剂是有效的。如顺式环 辛烯的全羟基化，在相转移催化剂的存在下，收率为 50%，而没有相转移催化剂时，收 率仅为 7%。 

      四氧化锇作氧化剂进行烯烃的全羟基化是一种较好的顺式羟基化的方法，收率教高。反应历程与高锰酸钾类似，形成环状的锇酸酯。由于锇酸酯不稳定，常加入叔胺（如吡啶）组成配合物，以稳定锇酸酯，加速反应。由于四氧化锇价贵且有毒，实验中常用催化量 的四氧化锇和其他的氧化剂，如与氯酸盐、碘酸盐、过氧化氢等共用。 

      碘与湿羧酸银为氧化剂，由碘与 2 mol 醋酸银或苯甲酸银所组成的试剂，称为 Prevost’s 试剂，该试剂可以氧化烯键成 1，2-二醇，当有水存在时（Woodward Reaction）得到顺 式 1，2-二醇的单酯，进而得到顺式加成的 1，2-二醇；在无水条件下（Prevost Reaction）， 则得到反式的 1，2-二醇 。

 顺式羟基化举例 

   A mixture of 2-[4-(benzyloxycarbonyl)piperazin-1-yl]-4-[trans-(2-buten-1-yl)oxy] quinazoline (1.30 g), a solution of osmium tetroxide in t-butanol (osmium tetroxide 106 mg/t-butanol 8.36 g) (312 mg) and 4-methylmorpholine N-oxide (382 mg) acetone is distilled off from the reaction mixture under reduced pressure, and the resultant product is diluted with ethyl acetate, and the mixture is washed with 10percent aqueous sodium sulfite solution and water. in water (2 ml)--acetone (15 ml) is stirred at room temperature for 14 hours.. The ethyl acetate solution is dried over anhydrous magnesium sulfate and evaporated to dryness under reduced pressure, and the residue is purified by medium pressure liquid column chromatography (eluent, chloroform:methanol=100:1, v/v) to give 2-[4-(benzyloxycarbonyl)piperazin-1-yl] -4-[(2RS,3RS)- (2,3-dihydroxybutan-1-yl)oxy]quinazoline (1.02 g) as foam. NMR (300 MHz, CDCl3--D2O, ppm): 1.32 (3H, d, J=6 Hz), 3.60 (4H, m), 3.8　 -4.0 (6H, m), 4.54 (1H, dd, J=6, 11.5 Hz), 4.63 (1H, dd, J=4, 11.5 Hz), 5.17 (2H, s), 7.16 (1H, ddd, J=1, 7, 8 Hz), 7.3-7.4 (5H, m), 7.51 (1H, dt, J=1, 8.5 Hz), 7.62 (1H, ddd, J=1.5, 7, 8.5 Hz), 7.89 (1H, dd, J=1.5, 8 Hz). 

2、反式羟基化

       烯键的反式羟基化重要的方法是过氧化物氧化法，另外 Prevost 反应也常用。过氧化物氧化烯键可生成环氧化合物，也可以生成 1，2-二醇，这主要取决于反应条件。首先过氧化物与烯键反应生成环氧化合物，当反应中存在一些可使环开裂的条件，则环 即被开裂成反式 1，2-二醇。双氧水、过氧甲酸和过氧乙酸为常用。其反应机理如下：

      反应分两步进行，先是过氧酸氧化烯键成环氧化合物，分离后加酸，酸从烯键平面的另 一侧进攻，再水解形成反式 1，2-二醇。

反式羟基化示例 

     The full amount of oleic acid (250g, 0.94 mole of unsaturation), formic acid (43.2g, 0.94 mole) and sulphuric acid (0.5g, 0.2percent) were added to a reactor, followed by 15percent of total amount of the required hydrogen peroxide (11g, 1.08 moles). This mixture of reactants was homogenize by stirring. As the stirring was carried out, an increase in temperature was observed, where the temperature of the mixture has risen from 25.deg.C to 60.deg.C. When the temperature started to decrease (55.deg.C), the remaining amount of hydrogen peroxide (62.6g), (total 1.08 moles) was then-added drop-wise with continuous stirring. The temperature of the reaction was maintained between 80-90.deg.C, by applying heat if necessary. The reaction was allowed to take place for 5 hours and the OOC is analyzed until it is less than 0.05; The reaction product from example 1 was poured into a separatory funnel and allowed to settle. The bottom spent acid layer was removed and the top upper organic layer was washed with chilled (5.deg.C to 10.deg.C) water until the pH of washing water and product were in the range of 2.5 to 3.0. The washed crude DHSA was dried under vacuum at 0.1 bar and at temperature 70.deg.C. Product was obtained in  74 - 79 % yield.