The Synthesis of Some Alkyl Hex-3-enopyranosiduloses

Abstract

Routes to methyl 3,4-dideoxy-a-D-glycero-hex-3-enopyranosidulose l a have been developed which use cheap readily-available chemicals, which are operable on a large scale and which have readily crystallizable materials as key intermediates (Scheme 4). Extensive use is made of reductive elimination of vicinal sulfonyloxy groups which is shown to operate equally well whether these groups on the pyranoside ring are in cis or tratls relationship. Contrary to other reported cases, it is found that the carbon-2 allylic hydroxyl goup is oxidized with manganese dioxide whether it is in pseudoaxial o r equatorial orientation.Differentes methodes utilisant des produits chimiques peu cohteux et facilement disponibles, pouvant facilement Ctre rentables a grande tchelle et irnpliquant des produits intermediaires facilement cristallisables, on CtC developptes afin d'obtenir le n~tthyl dideoxy-3,4 a-D-glycero hexeno-3 pyranosidulose l a (schema 4). Dans ces methodes, on a tres souvent utilist la reaction d'elimination rtductive des groupes sulfonyloxy vicinaux qui fonctionne bien, indtpendamment de la relation cis ou trans pouvant exister entre ces groupes sur l'anneau pyranosyde. Contrairement a ce qui a dtja tte rapporte dans d'autres cas. on a trouvt que le groupe hydroxyle allylique sur le carbone-2 est oxyde a I'aide du bioxyde d e manganese sans tenir compte de son orientation pseudoaxiale ou Cquatoriale.Can. .I. Chem., 51, 3357 (1973) [Traduit par le journal]

The stereochemistry of conjugate addition of lithium dialkyl cuprate reagents to some carbohydrate α-enones

“…calcd. for C10H19N07 : C 56.97, H 5.68, N 4.15; found: C 56.88, H 5.64, N 4.22. For component of Rf = 0.07: ir 3600 cm-', no carbonyl; nrnr data additional to those in Table 2: 6 3.3-4.1 (m, 2, 0CHZCH3), 1.22 (t,3,0CH,CH3),1.25 (s,3,) exchangeable OH.…”

“…For compound of R, = 0.29: ir 3600cm-', no carbonyl; nrnr data additional to those in Table 2: 6 3.1-4.2 (m, 2, 0CH2CH3), 1.25 (t,3,0CHzCH3), 1.26 (s,3,CCH,), aromatic and exchangeable OH, J12 = 3 Hz, JZ3 = 10 HZ.…”

“…For compound 5c: Rf = 0.52 in ethyl acetate -petroleum ether (30-60°C) (1 : l); nrnr data additional to those in Table 2: 6 3.60 and 3.85 (m, 2, 0CHAHBCH3, JAB = 9.5 Hz), 1.25 (t, 3, Ethyl 2,3-Dideoxy-4-C-uinyl-~1-~-thueo-hex-2-enopyranoside, 6c The chromatographic fractionation described immediately above (see also Table 1) afforded con~pound 6c, Rf 0.19 in ethyl acetate -petroleum ether (1: 1); ir 3600 cm-', no carbonyl; nrnr data additional to those in Table 3: 6 3.6-4.2 (m, 2, 0CHZCH3), 1.25 (t,3,). For -CH7=CH8H9: 6 5.88 (dd, 1, H-7, J78 = 10.25, J7, = 17.13), 5.21 (dd, I , H-8, Jsg = 1.80), 5.35 (dd, 1, H-9).…”

“…Evaporation under reduced pressure yielded 9.5 g of crude product which was eluted down a column of silica gel using 50% ethyl acetate -petroleum ether (30-60°C). Compound 12 (8.1 g, 83%) was a crystalline substance, mp 164-165°C; [a]DZ3 +4.6' (C 3.10, chloroform); nmr data for 12 additional to those in Table 2: 6 3.56 (s,3,OCH, (m, 15, aromatic), Jlz = 0, J3ax4 = 2.5, J3eq4 = 6.0, J3ax3eq = 15.0, J 5 6 = 6.0, J 5 6 , = 7.0, J 6 6 ' = 12.0. Anal.…”

“…On Ctudie les reactions conjugutes d'addition-alkylation des dialkyl cuprates de lithium aux hexCno-2 pyrannoulosides-4 (I), hexkno-3 pyrannoulosides-2 (2) et hexeno-1 pyrannoulose-3 (3). Une etude developpee sur 1 montre que le systkme homogene utilisant le complexe soluble tri-nbutylphosphine-cuivre(1) est moins satisfaisant que le milieu hetkrogirne dans lequel I'iodure de cuivre(1) est utilise.…”