Categories: C-O Bond Formation >
Synthesis of 1,2-diols
Effective hydrolysis of epoxides and aziridines was conducted in water at 60 or 100°C. Other types of nucleophile such as amines, sodium azide, and thiophenol could also efficiently open epoxides and aziridines in hot water. Hot water acts as a modest acid catalyst, reactant, and solvent in the hydrolysis reactions.
Z. Whang, Y.-T. Cui, Z.-B. Xu, J. Qu, J. Org. Chem., 2008, 73, 2270-2274.
Epoxides can be opened under neutral conditions with alcohols and thiols in the presence of a catalytic amount of erbium(III) triflate, affording the corresponding β-alkoxy alcohols and β-hydroxy sulfides in high yields. In water, epoxide ring opening occurs to produce the corresponding diols in good yields.
R. Dalpozzo, M. Nardi, M. Oliverio, R. Paonessa, A. Procopio, Synthesis, 2009, 3433-3438.
Epoxides undergo rapid ring opening with a range of alcohols in the presence of catalytic amount of carbon tetrabromide under mild and convenient conditions to afford the corresponding β-alkoxy alcohols and 1,2-diols in high yields with high regioselectivity.
J. S. Yadav, B. V. S. Reddy, K. Harikishan, Ch. Madan, A. V. Narsaiah, Synthesis, 2005, 2897-2900.
Epoxides can be cleaved in a regio- and stereoselective manner under neutral conditions with water, alcohols and acetic acid in the presence of catalytic amounts of decatungstocerate(IV) ion, affording the corresponding diols, β-alkoxy and β-acetoxy alcohols in high yields.
V. Mirkhani, S. Tangestaninejad, B. Yadollahi, L. Alipanah, Tetrahedron, 2003, 59, 8213-8218.
Lithiated epoxides react stereospecifically with boronates to give syn-1,2-diols, a process that can be used iteratively to create triols containing four stereogenic centers.
E. Vedrenne, O. A. Wallner, M. Vitale, F. Schmidt, V. K. Aggarwal, Org. Lett., 2009, 11, 165-168.
Aldehyde α-hydroperoxides can be accessed from α-substituted acroleins with triethylsilane and water under Pd/C catalysis and aerobic conditions via a Pd/C-catalyzed conjugate reduction step and a subsequent hydroperoxidation step. Upon reduction, 2,2-disubstituted 1,2-diols are obtained.
S. Tuokko, P. M. Pihko, Synlett, 2016, 27, 1649-1652.
Transformation of epoxides to β-alkoxy alcohols, acetonides, and α-alkoxy ketones is achieved by using molybdenum(VI) dichloride dioxide (MoO2Cl2) as a catalyst. Alcohol, aldehyde, oxime, tosyl, and tert-butyldimethylsilyl functional groups are tolerated during the methanolysis and acetonidation of the functionalized epoxides.
K. Jeyakumar, D. K. Chand, Synthesis, 2008, 807-819.
A very efficient and highly regioselective ring-opening reaction of epoxides with benzoic acid and its derivatives in the presence of cat. amount of tetrabutylammonium bromide (TBAB) in anhydrous acetonitrile gave selectively protected diols.
A. Khalafi-Nezhad, M. N. Soltani Rad, A. Khoshnood, Synthesis, 2003, 2552-2558.
The reaction of chiral 1-aminoalkylepoxides with CO2, generated from acidic treatment of an aqueous solution of NaHCO3 at room temperature, efficiently afforded enantiopure cyclic carbonates with total selectivity. Carbonates were readily transformed into the corresponding diols by reaction with LiAlH4 or by basic hydrolysis.
J. M. Concellón, V. del Solar, S. Carcía-Granda, M. R. Díaz, J. Org. Chem., 2007, 72, 7567-7568.