But-2-ene-l,4-diol

The palladium-promoted conversion of 1,3-dienes to pyrroles proceeds via 4-acetoxy-2-alkenylpalladium complexes (Scheme 50g) (81CC59), and a similar pathway may be involved in the palladium mediated reaction of but-2-ene-l,4-diol with primary amines to give A-substituted pyrroles (74CC931). 

Replacing hex-3-ene with trans-1,4-dimethoxybut-2-ene resulted in slightly slower reactions, but gave comparable yields of cross-metathesis products. The desired reactions did not take place, however, when ris-but-2-ene-l,4-diol was used as the acyclic substrate. 

Bromo-l,4-dihydroxybutan-2-one 1,4-bisphosphate (31) has been prepared from the protected bromohydrin of cw-but-2-ene-l,4-diol.95 Nucleophiles rapidly displace bromide ion from (31), and the latter has been used as an affinity label for ribulose-bisphosphate carboxylase. In this case two sites are labelled in each enzyme molecule, the two molecules of (31) being linked to the enzyme by two different lysine residues.96... 

Z)-But-2-ene-l,4-diol.24 But-2-yne-l,4-diol (20g) is dissolved in methanol (350ml) and hydrogenated at atmospheric pressure in the presence of 0.5 per cent palladium-on-calcium-carbonate (2.0 g). After 24 hours one equivalent of hydrogen (5650 ml) will be absorbed. The catalyst is then separated and the filtrate distilled, giving (Z)-but-2-ene-l,4-diol as a colourless oil (15.7g, 77%), b.p. 134-135 °C/15 mmHg, n 5 1.4716. The product forms a dibenzoate (prisms from aqueous methanol), m.p. 69-70 °C. 

Using this method, synthesis of functionalized substituted cyclopropanes can be achieved via nucleophilic alkylation of the monoacetates of but-2-ene-l,4-diols 18 with malonates (and similar stabilized) carbanions in the presence of a palladium(0) catalyst. Subsequent acylation of the second hydroxyl function and subsequent treatment with base in the presence of the palladium(0) catalyst leads to intramolecular nucleophilic alkylation. This method and similar conversions have been applied to numerous other cyclopropane ring constructions. - - ... 

The simplest example here is the oxidation of cw-but-2-ene-l,4-diol, which gives fnran via the hydroxy-aldehyde - the two degrees of unsatnration being the carbonyl and carbon-carbon donble bonds. ... 

Oxiranes are of considerable importance as intermediates for multistep stereospecific syntheses of complex target molecules, because closing and opening reactions of the oxirane ring often occur without side reactions. Moreover, they proceed stereospecifically. The first steps in the total syntheses of all 16 stereoisomeric hexoses may serve as an example. These syntheses start from ( )-but-2-ene-l,4-diol, 1, which is obtainable from acetylene and formaldehyde via butyne-l,4-diol [12]. 

The simplest example here is the oxidation of c/x-but-2-ene-l,4-diol, which gives... 

Forthe Cs-aldehyde moiety, there are several access routes available. A comparatively simple option is the hydroformylation of l,2-diacetoxybut-3-ene, which is obtainable from but-2-ene-l,4-diol by esterification with acetic anhydride and a copper-catalysed rearrangement. Critical for this synthetic route is to control the regioselectivity of the hydroformylation. A recently developed process to prepare vinyloxirane from butadiene over a silver catalyst opens up a second attractive approach. [56, 57]... 

Azido-sugars are frequently prepared by reaction of epoxides with azide ion. 3-Azido-3-deoxy-L-threose 68 was synthesized from cu-but-2-ene-l,4-diol 66 via the Sharpless asymmetic epoxidation product 67, and was converted into 6-azido-6-deoxy-L-galocro-heptulose 69 by an enzyme-catalyzed aldol condensation (Scheme 13). 3-Azido-3-deoxy-L-etythrose, and thence 6-azido-6-deoxy-L-g/uco-heptulose were obtained in a similar way via 4-rerf-butyldiphenylsilyoxy-rraiu-but-2-enal. These and two other azido-heptulose isomers made from the enantiomeric 3-azido-3-deoxy-tetroses, were converted to a- and P-l-homonojirimycin and homomannonojirimycin on hydrogenation. Ethyl 3-azido-2,3-dideoxy-D-eryr/iro-pentopyranoside and its 3-C-methyl analogue 71, R=H or Me, were synthesized from crotonaldehyde or 3-methyl-2-... 

Preparative Methods compound (1) can be prepared in two steps as shown in eq 1 first aziridination of c/s-but-2-ene-l,4-diol (1 equiv) is done with TsNClNa (1.1 equiv) and PhMe3NBr3 (0.1 equiv) in acetonitrile at 25 °C for 3 days. This is foUowedby treatment of the diol with diisopropyl azodicarboxylate (DIAD, 1.5 equiv) and PPhs (1.5 equiv) in THE at —78°C for 1 h followed by stirring at 25 °C for 7 days. ... 

The vinylmagnesium derivatives (40), obtained by Cu -mediated anft-addition of Grignard reagents to primary a-acetylenic alcohols, can by hydrolysed to ( )-allylic alcohols (41) (Scheme 18) or, if = H, halogenated and then alkylated to yield (Z)-allylic alcohols (42)." Reaction of (40) with carbonyl compounds gives substituted but-2-ene-l,4-diols. ... 

Homologation of olefins by four carbon atoms is achieved by reaction of the derived borane (265) with buta-1,3-diene monoxide in the presence of catalytic amounts of oxygen. Trialkylboranes are also converted into the 4,4-dialkyl-c/j-but-2-ene-l,4-diols (266) in good yields by addition to a-lithiofuran and oxidation of the intermediate boroxarocyclohexenes (267) with hydrogen peroxide. ... 

Displacement of (Z)-but-2-ene-l,4-diol with PhS02Na generates sulfone 53, the dilithio derivative of which obtained by treatment with (Me3Si)2NLi adds to enantiomerically pure arylsulfinimine 54 at — 100°C. The major product 55 is obtained pure after recrystallization. Treatment of 55 with CF3COOH liberates the amine 56 that undergoes an intramolecular Mitsunobu substitution... 

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