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The k' pathway implicates a reaction between the doubly charged anion (RCHO 2 2−) and the aldehyde. The direct transfer of hydride ion is evident from the observation that the recovered alcohol does not contain any deuterium attached to the α-carbon when the reaction is performed in the presence of D 2 O.
Sodium hydride is the chemical compound with the empirical formula Na H. This alkali metal hydride is primarily used as a strong yet combustible base in organic synthesis . NaH is a saline (salt-like) hydride , composed of Na + and H − ions, in contrast to molecular hydrides such as borane , silane , germane , ammonia , and methane .
Alcohol oxidation is a collection of oxidation reactions in organic chemistry that convert alcohols to aldehydes, ketones, carboxylic acids, and esters. The reaction mainly applies to primary and secondary alcohols. Secondary alcohols form ketones, while primary alcohols form aldehydes or carboxylic acids. [1] A variety of oxidants can be used.
Trimethyl borate is the main precursor to sodium borohydride by its reaction with sodium hydride in the Brown-Schlesinger process: 4 NaH + B(OCH 3) 3 → NaBH 4 + 3 NaOCH 3. It is a gaseous anti-oxidant in brazing and solder flux. Otherwise, trimethyl borate has no announced commercial applications.
Other alkali metals can be used in place of sodium, and most alcohols can be used in place of methanol. Generally, the alcohol is used in excess and left to be used as a solvent in the reaction. Thus, an alcoholic solution of the alkali alkoxide is used. Another similar reaction occurs when an alcohol is reacted with a metal hydride such as NaH.
Fig. 1 shows an example of a diastereoselective CBS reduction being used to prepare a complex macrocyclic alcohol en route to the synthesis of 11-desmethyllaulimalide [22] (an analog of the antitumor agent laulimalide). The authors noted that CBS reduction was much more effective than using either lithium tert-butoxyaluminum hydride or L ...
The hydride adds to an electrophilic center, typically unsaturated carbon. Hydrides such as sodium hydride and potassium hydride are used as strong bases in organic synthesis. The hydride reacts with the weak Bronsted acid releasing H 2. Hydrides such as calcium hydride are used as desiccants, i.e. drying agents, to remove trace water from ...
The aldol addition product can be dehydrated via two mechanisms; a strong base like potassium t-butoxide, potassium hydroxide or sodium hydride deprotonates the product to an enolate, which eliminates via the E1cB mechanism, [9] [10] while dehydration in acid proceeds via an E1 reaction mechanism.