Malaprade鄰二醇氧化裂解反應

利用用高碘酸或高碘酸鈉，將1,2-二醇氧化斷裂得到相應的醛酮的反應，被稱為 Malaprade鄰二醇氧化裂解反應 。此反應最早由Malaprade在1928年首先報道【Malaprade, L. Bull. Soc. Chim. France 1928 , 43, 683.; Compt. Rend . 1928 , 186, 382】。由于溶解性的緣故，通常使用水作為溶劑，另外可以加入甲醇、乙醇、乙酸促進底物溶解。若要在非極性溶劑體系中反應，可用硅膠固載NaIO4反應效果較好。此反應與類似，通過形成環狀內酯裂解得到醛酮。此反應除了可以裂解鄰二醇，α-羥基羰基化合物，1,2-二羰基化合物，α-氨基醇，α-氨基醇也可以被裂解，在上述底物中羥基側片段轉化為醛，羰基側片段轉化為羧酸，氨基側片段轉化為醛和氨。此反應在酸性環境下反應速率大于中性和堿性。此反應常用于糖及其類似物的降解。高碘酸鈉可作為四氧化鋨的共氧化劑使用，能將烯烴也在溫和條件下氧化斷裂【 】。

反應機理

反應實例

【J. Org. Chem., 1994, 59, 6614】

A large, magneticstir bar isadded to the flask that contains the crude solid diacetonide from procedure Aabove and 700–800 mL of dichloromethane (10 mL/g of diacetonide) is added. The flask is equipped with a condenser and heatingmantle, and the slurry is stirred vigorously and heated to reflux until thesolids are digested to an even consistency. The mantle is removed, the slurryis allowed to cool below reflux, and Celite (10 g) is added with stirring. The contents are furthercooled to room temperature and vacuum-filtered through a pad of Celite on a glass frit filter into a three-necked,2-L vessel. The flask is rinsed with 50 mL of dichloromethane and the rinse is filtered through thefunnel. The 2-L vessel is then equipped with an overhead stirrer, thermometer, and water bath,and stirring is begun at 300–350 rpm. A solution of 30–40mL of saturated aqueous sodium bicarbonate (0.4 mL/g of diacetonide) is added with stirring,followed by 130–140 g of sodiummetaperiodate (2.0 mol equiv), addedportionwise over 2–3 min. The resulting mixture is stirred while the internaltemperature is maintained below 35°Cwith water bath cooling. After the solution is stirred for 2 hr, 35–50 g of magnesium sulfate (0.5 g/g of diacetonide) is added andstirring is continued for 20 min. The slurry is vacuum-filtered through a glassfrit filter into a 2-L, one-necked, round-bottomed flask.The filter cake is removed, transferred back into the three-necked vessel, 200 mL of dichloromethane isadded, and the resulting slurry is stirred for 10 min. The slurry isvacuum-filtered and the filtrate is added to the one-necked flask.

The filtrate-containing flask is equipped with a 12"-Vigreux column, distillationhead, receiver, and heating mantle, and dichloromethane is removed by distillation (headtemperature to 40°C). Theresidual oil is cooled and transferred to a 250-mL,round-bottomed flask and the flask is equipped with a simpledistillation head, cow receiver, and heating mantle. After a brief forerun (2–3 g),product is collected by distillation at 30 mm(65–120°C)into a chilled receiver (5°C)to afford 54–68 g(75–85%) of crude 2,3-O-isopropylidene-D-glyceraldehyde. The crudeproduct is transferred to a 100-mL, round-bottomed flaskequipped with a 6"-Vigreux column, cowreceiver, and heating mantle, and redistilled at 30 mm, collecting the fraction distilling at 67–73°Cinto a chilled receiver to afford 50–64 g of product (70–80%,34–45% overall).

【Organic Syntheses, Coll. Vol. 9, p.450; 1995，Vol. 72, p.6】

OsO4(cat.)-NaIO4-2,6-lutidine的反應條件下、烯烴能被氧化斷裂。加入2，6-二甲基吡啶（lutidine）是為了抑制副反應，避免α-羥基酮的生成。

【Org. Lett. 2004, 6, 3217】

【J. Am. Chem. Soc.2007, 129. 4540】

參考資料

一、Comprehensive Organic Name Reactions and Reagents, by Zerong Wang，1807-1810.

二、http://www.chem-station.com/cn/reactions/%e6%b0%a7%e5%8c%96%e5%8f%8d%e5%ba%94/2014/03/%e9%a9%ac%e6%8b%89%e7%a0%b4%e7%91%9e%e5%be%b7%e4%b9%99%e4%ba%8c%e9%86%87%e6%b0%a7%e5%8c%96%e6%96%ad%e8%a3%82-malaprade-glycol-oxidative-cleavage.html

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