Protected pyruvic aldehyde

While several metal-catalysed approaches to solve the task of generating fl tz-l,2-diols have been developed, this method remains remarkable, since it represents the first small molecule-catalysed, catalytic version of this transformation. The starting materials do not need activation or protection, and the reaction can be performed under standard conditions without further precautions. The selectivity of the reaction potentially results from a hydro Q acetone enamine-initiated transition state (5). More recently, Enders et al. applied a related method to the organocatalytic synthesis of sialic acid precursors (Scheme 5.6). Protected pyruvic aldehyde (6) was reacted with several aldehydes, forming the desired aldols (7) in moderate yields, but good selectivities (31-51%, 90-92% de, 73-99% ee). The conditions were optimised to limit detrimental side reaetions sueh as Mannich elimination or formation of the aeetal self-aldolisation produet. While generally easily applicable and robust, the method laeks effieiency in one key parameter, its reaction time. This limitation, combined with moderate yields unfortunately prevents a scale-up to or beyond the pilot plant. 

Cyanide is a nucleophile known to react with various carbonyl moieties like ketones and aldehydes to yield cyanohydrin derivatives (Morrison and Boyd, 1976). Sodium pyruvate (Schwartz et al, 1979), a-ketoglutarate (Moore et al, 1986), pyridoxal-5 -phosphate (Keniston et al, 1987), and many other carbonyl compounds and their metabolites or nutrients which interact with cyanide to form cyanohydrin complexes (Way, 1984 Niknahad et al, 1994 Bhattacharya and Tulsawani, 2008) have been reported to afford significant protection against acute cyanide poisoning in vitro or in vivo. Out of all these agents, a-ketoglutarate, either alone or with sodium thiosulfate, has been considered to be a promising antidote for cyanide (Borowitz et al. 

Two groups have published details of new routes for large-scale synthesis of phosphoenolpyruvate salts (31) from pyruvic acid, via Perkow reactions between bromopyruvic acid and trimethyl phosphite. The tris-cyclohexylamine salt of L-ascorbic acid 2-phosphate (32), a stabilized form of vitamin C, has been prepared by addition of tris(trimethylsilyl) phosphite to a protected derivative of L-ascorbic acid. Tetraethylamidophosphorous acid anhydride (33) reacts with aldehydes to give tervalent-quinquevalent phosphorus products (34). ... 

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