Erythrose, deriv

To study asymmetric induction from the nitrone part in 1,3-dipolar cycloaddition to styrene, D-erythrose derived nitrones (479 a-c) have been used. Cycloaddition of nitrones (479 a-c) to styrene, in boiling toluene for 10 h, affords a mixture of four diastereomeric 3,5-disubstituted isoxazolidines (481 a-c-484 a-c) in high yields (82%-94%) (Scheme 2.237) (208). 

By ozonolysis and subsequent in situ acylation in the presence of base, the enantiopure 1,2-oxazine 177 (R = Bn) was converted to the highly functionalized a-amino-/ -hydroxy ester 181 along with a minor product 5-hydroxylated oxazine 182 <2005EJ0998>. Similarly, D-erythrose-derived syn- and 7 // -compounds 183 afforded the expected diastereomeric syn- and /f-oxazine esters 184 and 5-hydroxylated oxazine 185 <2005EJ0998>. The arbinose-derived anti-configured 1,2-oxazine 186 was subjected to an ozonolysis/elimination sequence which provided the desired functionalized a-amino ester 187 in 75% yield. 

Additions of the transient y-OMOM crotyl indium chloride reagents to a-oxyge-nated aldehydes are strongly reagent-controlled. Thus the (R) and (S) reagents add to protected threose and erythrose aldehydes with high diastereoselectivity (Eq. 59) [75]. These additions are complementary to those previously effected with the y-BusSn counterparts (Eq. 45). It is thus possible to prepare precursors to the eight diastereomeric hexoses and their enantiomers from threose- and erythrose-derived aldehydes and their enantiomers plus the a-OMOM crotyl tributylstannane enantiomers. 

Dondoni and coworkers [63] have shown that homologation of a-hydroxycarbaldehydes can be achieved with high antiselectivity by addition of 2-(trimethylsilyl)thiazole (42) (Scheme 13.25). For instance, D-glyceraldehyde acetonide (R)-24 reacts with 42 giving 43 in 96% yields with the anti vs. syn diastereoselectivity better than 95 5. Release of the aldehyde requires protection of the alcohol as a benzyl ether, methylation of the thiazole generates intermediate 43 Me that is not isolated but reduced in situ with NaBH4 to give thiazoline 43 H. Mercury(II)-catalyzed hydrolysis liberate the semiprotected D-erythrose derivative d-45 in 62% overall yield [64]. Methylation of the thiazole moiety can also be achieved with methyl triflate instead of Mel, and copper(II)chloride can be used instead of mercury(II)chloride [65]. 

Marshall, J A, Seletsky, B M, Luke, G P, Synthesis of protected carbohydrate derivatives through homologation of threose and erythrose derivatives with chiral y-alkoxy allylic stannanes, J. Org. Chem., 59, 3413-3420, 1994. 

Combining the D-erythrose derivative 26 obtained by L-proline-catalyzed dimerization of (t-Bu)Ph2SiOCH2CHO with enoxysilane 27 in Mukaiyama aldol reactions catalyzed by various Lewis acid, MacMillan and co-workers have realized efficient, two-step syntheses of semi-protected D-glucose (28G), L-mannose (28M) and L-allose (28A) (O Scheme 23) [148]. Using D-proline to generate tetrose 29 and its condensation with 27b, the semi-protected D-glucose derivative 30 was obtained in two steps [149]. 

Erythrose derivatives such as 2-4, with a free hydroxy function, offer many possibilities for regioselective conversions in addition, the free hydroxy group in 2 or 3 does or may influence the regio- and stereoselectivity of additions to the carbonyl group. 2,4-O-Ethylideneerythrose, because of its di- or oligomeric form, is configurationally stable at room temperature and can be stored for several months at room temperature.9-18... 

According to lUPAC nomenclature, the first residue is an a-L-erythrose derivative. 

Synthesis from erythrose a-Homonojirimycin (1) has been synthesized from the erythrose derivative by Sharpless asymmetric epoxidation to the 5y -epoxide 48... 

Synthesis from erythrose An efficient approach for the synthesis of (-l-)-trihy-droxyheliotridane (180) via a chiral erythrose derivative has been reported (Scheme 16). Wittig reaction of 2,3-(9-isopropylidene-L-erythrose (172) with Ph3P=CHCH=CHC02Et produced a 1 5 mixture of the ( , )-173 and (Z,A)-174 isomeric dienes, respectively. The diene 173 could be quantitatively obtained by isomerization of 174 with E. The diene 174 was converted to the azide 177, which upon boiling in benzene gave the vinyl aziridine 176. Pyrolysis of 176 furnished the pyrrolizidine 178. On the other hand, the diene 173 was... 

Synthesis from o-erythrose The D-erythrose derivative 9 has been used for the synthesis of (15, 2i ,8ai )-l,2-dihydroxyindolizidine (13) by transformation into the azide 10 (Scheme 2). Intramolecular cycloaddition of 10 in boiling benzene produced the bi-cyclic iminium ion 11, which underwent sodium borohydride reduction to give 12, followed by acid hydrolysis of the isopropylidene group to provide 13 in 49% overall yield from 10. 

The Vasella group [65] reported the synthesis of carboxyhc acid 77 and the corresponding phosphonic-acid isoster 78 from o-erythrose derived imines 74-76 (Scheme 19). Despite expectations, none of the synthesized compounds exhibited a significant inhibitory in vitro activity against the siahdases of Vibrio cholerae. Salmonella typhimurium. Influenza A, and Influenza B virus. 

Fisera et al. have [22,23] found a very unusual and rare reversal of regioselect-ivity of the cycloaddition of TBDPS-protected D-erythrose-derived nitrone... 

Aldol condensation of 2,3-0-ethylidene-D-erythrofuranose with formaldehyde gave the 2-C-hydroxymethyl-erythrose derivative (6), an isomer of apiose, which was characterized through aldonolactone and glycoside derivatives 2,3-O-isopropylidene-D-ribose similarly yielded D-hamamelose (2-C-hydroxymethyl-D-ribose) after deprotection. ... 

AnhydrO Alditols- An improved preparation of the four epoxybutanediol acetonides 24 (RR,RS,SR or SS) from L-ascorbic acid or D-isoascorbic acid (cf. Vol. 24, p. 195, ref. 16) has been described. The conversion of these isomers into enantiomerically pure glyceraldehyde derivatives, threose/erythrose derivatives or 2,3-anhydro threose/erythrose derivatives by initial treatment of 24 with various organometallic reagents is also reported. These latter compounds are useful building blocks for the synthesis of acyclic oxygenated fatty acid metabolites. 

Alkoxyoxetanes, e.g. (38), have been obtained by formal [2 + 2]cycloadditions between 2,3-0-isopropylidene-flWe/iydo-D-erythrose derivatives and vinyl ethers, and have been converted to 2-deoxy-n-hexose derivatives, e.g. (39) and (40). Palladium(II)... 

Allylic alcohols of use in the synthesis of deoxy sugars have been synthesized by reaction of 4-deoxy-L-erythrose derivative (47) (available from the products of cinnamaldehyde in fermenting bakers yeast) with various metal-alkenyl reagents the major isomer (48), formed with vinylmagnesium bromide, was thus converted into the 6-deo3Qr-L-altrofuranosides (49) (Scheme 9). Full details on the synthesis of 2-deojy-L-sugars from l-... 

Deoxy-L-threose and -erythrose derivatives are available from ethyl 0-benzyl-L-lactate by chain elongation with the formyl anion eguivalent (21) and subseguent reduction of ketone (22) (Scheme 5). The anion of methyl phenyl sulphone has been added... 

Deoxy-sugars have also been constructed from noncarbohydrate starting materials. One-carbon extension of the L-lactate derivative (59) gave dithioacetal (60) from which various 4-deoxy-L-threose and -erythrose derivatives were synthesised. Tetramethylammonium triacetoxyborohydride has been used to selectively reduce -hydroxy-ketones to anti-1.3-diols. as in the conversion of ketones (61) and (62) to diol (63) and triol (64),... 

Tetroses.- The D- and L-erythrose derivatives (3) and (4), respectively, are available from chlorobenzene by the enantiodivergent route shown in Scheme 3, yjg... 

The only divergent opinion is that of Wenkert, who postulates that the harmala bases are derived directly from carbohydrate precursors by way of an anthranilate-erythrose-derived intermediate and not by way of tryptophan or tryptamine. This interesting alternative hypothesis, which is based almost entirely on structural arguments, was put forward as one aspect of a general carbohydrate hypothesis of alkaloid biogenesis. In a few cases where the alternative hypotheses are amenable to direct differential experimental test the carbohydrate hypothesis has not been substantiated. Whether or not it is applicable to the biogenesis of the harmala bases has not yet been investigated by biosynthetic experiment. 

The reaction of alkenyl ethers with aldehydo-D-erythrose derivatives mediated by boron tiifluoride etherate gave rise to branched-hexosides depicted in Scheme 13. ... 

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