Tin(ii) Enediolate From Methylglyoxal

Abstract

Methylglyoxal is successfully converted to the tin(II) enediolate on treatment with activated metallic tin. The tin(II) enediolate reacts with several aldehydes to give α, β-dihydroxyketones in good yields.

Thermochemical Considerations of Metal Enolates

“…We note the facile formation of such a species by reaction of methylglyoxal with activated elemental tin 95 . Assumed monomeric, we note that this metallocycle 15 is formally a 6π-system analogous to 1,3-dioxolen-2-one (vinylene carbonate).…”

Multinuclear enantiopure titanium self‐assembly complexes—synthesis, characterization and application to organic synthesis

“…They were isolated with a high degree of anti-diastereoselectivity. 49,50,54 These results demonstrate the feasibility of a metallorganic approach to aldol adducts of hydroxaycetone. Moreover, the obtained syn-configured aldol adducts make this method to a valuable addition to the well-established anti-selective proline-catalysis.…”

High‐Yielding Diastereoselective syn‐Dihydroxylation of Protected HBO: An Access to D‐(+)‐Ribono‐1,4‐lactone and 5‐O‐Protected Analogues

“…Under these conditions, HBO-TBDMS-2OH, HBO-TBDPS-2OH and HBO-Bn-2OH were obtained in 60, 62 and 60 % yields, respectively, comparable to that obtained with KMnO 4 /dicyclohexano-18-crown-6 ether. [24] Upjohn dihydroxylation conditions, [29][30][31] involving osmium tetroxide as catalyst and N-methylmorpholine-N-oxide (NMO) as oxidant, were then investigated ( Table 1, entries 3, 7 and 11). Among the different solvent mixtures tested (i.e., methanol, acetone-water and acetone-water-butanol), acetone/ water proved the most relevant one and gave access to dihydroxylated derivatives of HBO-TBDMS (HBO-TBDMS-2OH), HBO-TBDPS (HBO-TBDPS-2OH), and HBO-Bn (HBO-Bn-2OH) in moderate yields, 50, 55 and 12 % respectively.…”

“…Another route consists in first protecting the primary alcohol of HBO with bulky groups to hinder the upper face of the molecule, then performing the asymmetric syn-dihydroxylation of the α, -unsaturation in presence of KMnO 4 (1.25 eq) and dicyclohexano-18-crown-6 ether (10 mol-%) in CH 2 Cl 2 at -42°C. [24] Although this procedure provides 5-O-protected D-(+)-ribono-1,4-lactone in d.r. between 12:1 and 50:1 depending on the protecting group used, the oxidizing agent is used in stoichiometric amounts, the yields remain low to average (<66 %) -due to overoxidation of the resulting diol -and energy-demanding low temperature control is required.…”