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A common diol reaction to produce a cyclic ether. 1,2-diols and 1,3-diols can be protected using a protecting group. [13] Protecting groups are used so that the functional group does not react to future reactions. Benzylidene groups are used to protect 1,3-diols. [13]
Although the classic substrate for the Criegee oxidation are 1,2-diols, the oxidation can be employed with β-amino alcohols, [10] α-hydroxy carbonyls, [11] and α-keto acids, [12] In the case of β-amino alcohols, a free radical mechanism is proposed. The Criegee oxidation can also be employed with 2,3-epoxy alcohols forms α-acetoxy carbonyls.
A [3+2]-cycloaddition with the alkene (3) gives the cyclic intermediate 4. [ 9 ] [ 10 ] Basic hydrolysis liberates the diol ( 5 ) and the reduced osmate ( 6 ). Methanesulfonamide (CH 3 SO 2 NH 2 ) has been identified as a catalyst to accelerate this step of the catalytic cycle and if frequently used as an additive to allow non-terminal alkene ...
Through a variety of mechanisms, the removal of a hydride equivalent converts a primary or secondary alcohol to an aldehyde or ketone, respectively. The oxidation of primary alcohols to carboxylic acids normally proceeds via the corresponding aldehyde, which is transformed via an aldehyde hydrate (gem-diol, R-CH(OH) 2) by reaction with water ...
In cyclic systems, the reaction presents more features of interest. In these reactions, the stereochemistry of the diol plays a crucial role in deciding the major product. An alkyl group which is situated trans- to the leaving –OH group may migrate to the carbocation center, but cis- alkyl groups migrate at a very low rate.
A second benzoate anion reacts with the intermediate to produce the anti-substituted dibenzoate product, which can then undergo hydrolysis to yield trans-diols. [21] The Prevost reaction mechanism. The Woodward modification of the Prévost reaction yields cis-diols. Acetate anion reacts with the cyclic iodinium ion to yield an oxonium ion ...
Two ketyl groups react in a coupling reaction yielding a vicinal diol with both hydroxyl groups deprotonated. Addition of water or another proton donor gives the diol. With magnesium as an electron donor, the initial reaction product is a 5-membered cyclic compound with the two oxygen atoms coordinated to the oxidized Mg 2+ ion.
Particularly common spiro compounds are ketal (acetal) formed by condensation of cyclic ketones and diols and dithiols. [15] [16] [17] A simple case is the acetal 1,4-dioxaspiro[4.5]decane from cyclohexanone and glycol. Cases of such ketals and dithioketals are common.