S 4-formyl

Treatment of m-butyl (S )-4-formyl-2,2-dimethyl-3-oxazolidinccarboxylate ( Garner aldehyde, 3), readily available from /V-Boc-l-serine and configurationally extremely stable49,50, with various nucleophiles preferentially yields the n n(nonchelation)-diastereomeric amino alcohols 4 in high chemical yield51 -55,57-61. 

Under a nitrogen atmosphere 0.23 g (1 mmol) of tm-butyl (S)-4-formyl-2,2-dimethyl-3-oxazolidinecar-boxylate(3) is dissolved in 5 mL ofabs. THF. The clear solution is stirred, cooled to —78 °C, then a solution of 1.3 mmol of the Grignard or lithium reagent is added dropwise. The mixture is stirred at — 78 °C for a further 1 h, then quenched by the addition of 20 mL of sat. aq NH4C1. After dilution with II20 the aqueous... 

SYNTHESIS OF 1,1 -DIMETHYLETHYL (S)-4-FORMYL-2,2-DIMETHYL-3-OXAZOLIDINECARBOXYLATE BY OXIDATION OF THE ALCOHOL... 

Although planar chirality has not been found in nature so far, biological tools can be used for resolution of planar chiral molecules. The synthesis of enantio-merically pure (S)-4-formyl[2.2]paracyclohane (>99% ee) (S)-155 and (R)-4-hydroxymethyl[2.2]paracyclophane (R)-156 (>78% ee) was achieved by bioreduction in 49 and 34% yield respectively. From several mircoorganisms screened only one strain of the yeast Saccharomyces cerevisiae showed a stereospecific reduction of the planar chiral substrate. Despite the high enantiomeric ratio it was necessary to maintain the conversion of the process at almost 50% in order to obtain high enantiomeric excesses of both substrate and reduction product [101]. 

Imidazole, 2-ethyl-1 -(o-nitrophenyl)-cyclization, S, 431 Imidazole, 4-ethyl-2-phenyl-oxidation, S, 405 Imidazole, ethynyl-Michael addition, S, 437 Imidazole, 4-ethynyl-2-phenyl-synthesis, S, 494 Imidazole, 1-formyl-reactions, S, 452 Imidazole, 2-formyl-mass spectra, S, 360 Imidazole, 4-formyl-synthesis, S, 475-476 Imidazole, 2-formyl-1,5-dimethyl-mass spectra, S, 360 3-oxide... 

Imidazole, 4-formyl-5-hydroxy-l-phenyl-mesoionic, 5, 372 Imidazole, 2-formyl-1-methyl-mass spectra, S, 360 Imidazole, 2-formyl-l,4,5-trimethyl-... 

Pyrazole, 3-ethoxycarbonyl-3 (5 ),5-dimethyl-5 (3 )-pyrazol-l-yl-reduction, 5, 260 Pyrazole, ethynyl-reactions, 5, 261 Pyrazole, 4-formyl-IR spectra, S, 201 NMR... 

If a chiral aldehyde, e.g., methyl (27 ,4S)-4-formyl-2-methylpentanoate (syn-1) is attacked by an achiral enolate (see Section 1.3.4.3.1.), the induced stereoselectivity is directed by the aldehyde ( inherent aldehyde selectivity ). Predictions of the stereochemical outcome are possible (at least for 1,2- and 1,3-induction) based on the Cram—Felkin Anh model or Cram s cyclic model (see Sections 1.3.4.3.1. and 1.3.4.3.2.). If, however, the enantiomerically pure aldehyde 1 is allowed to react with both enantiomers of the boron enolate l-rerr-butyldimethylsilyloxy-2-dibutylboranyloxy-1-cyclohexyl-2-butene (2), it must be expected that the diastereofacial selec-tivitics of the aldehyde and enolate will be consonant in one of the combinations ( matched pair 29), but will be dissonant in the other combination ( mismatched pair 29). This would lead to different ratios of the adducts 3a/3b and 4a/4b. 

S)-A -Formyl-.Y-(2,.3,4-tri-D-pivaloyl-z-n-arabinopyranosylWert-leucine ferf-Butylamide Typical Procedure76 7S ... 

The base-catalysed ring contraction of 1,3-dioxepanes offers an attractive route to 4-formyl tetrahydropyrans (Scheme 14) , whilst fused exo-cyclic dienes 27 result from the radical cyclisation of alkenyl iodides 26 (Scheme 15) <00OL2011>. Intramolecular radical addition to vinylogous sulfonates is highly stereoselective, leading to the ci s-2,6-disubstituted tetrahydropyran (Scheme 16) . 

D1methylethyl (S)- or (R)-4-Formyl-2,2-dimethy1-3-oxazolidinecarboxylate A Useful Serinal Derivative P. Garner and J. M. Park, Department of Chemistry,... 

Oxidation of the acetyl group in 2-acetyl-3,S-dialkyl derivatiyes of 1 and 2 with iodine in pyridine, and of the formyl group in 5-ethyl-2-formyl- and 2-formylthieno[2,3-6]thiophene, and 4-formyl- and 6-formylthieno[3,4-6]thiophene (194 and 195) with silver oxide, was performed to verify the structures of the acetylation and formylation products. 

This reaction proceeds without racemization, however, structurally similar hydrazones required different reaction conditions. This was further investigated with the SAMP-hydrazones of tert-butyl 4-[(5)-2-formyl-6-(3-dimethylthexylsilyloxyphenyl)hexyl]-l-benzenecarboxylate and tert-butyl 4-[(S)-2-formyl-7-(3-dimethylthexylsilyloxyphenyl)heptyl]-l-benzenecarboxylate. 

So erhalt man aus 4-Formyl-benzofurazan-l-oxid mit primaren Aminen die entsprechenden 2-Alkyl-7-nitro- und 2-Aryl-7-nitro-2H-indazole (s.Bd.E8b)270 ... 

Oxazolldinecarboxyllc acid, 4-formyl-2,2-dimethyl-, 1,1-dimethylethyl ester, (S)- (11) (102308-32-7)... 

An important class of cationic dyes, particularly for yellow to bluish-red hues, is derived from Fischer s base by condensation with 4-formyl-substituted anilines, or from Fischer s aldehyde (which may be prepared from Fischer s base via Vilsmeier formylation (B-71MI11205)) and an aromatic amine (Scheme 3). There are many examples of resonating charge dyes of this type which include a variety of aromatic amines and aldehydes. Of heterocyclic interest are the dyes formed by condensation of Fischer s aldehyde with... 

S)-4-Methyl-1 -hexene (12), (+) (S)-4-methyl-2-hexene, and ( + )(S)-5-methyl-l-heptene (12) were synthesized and subjected to hydroformylation under a relatively high carbon monoxide pressure. The main product in all instances was the result of formylation of the terminal carbon atom on or next to the double bond of the starting olefin. The optical yields of these products were about 94% (Table I). 

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