Stereoselective synthesis of (2R,3S,4S,5R)-trans-3,4-dihydroxy-5-(4-fluorophenoxymethyl)-2-(1-N-hydroxyureidyl-3-butyn-4-yl)tetrahydrofuran and (2R,3S,4S,5R)-trans-5-ethynyl-2-(4-fluorophenoxymethyl)-3,4-O-isopropylidene tetrahydrofuran from mannose diacetonide

Stereoselective synthesis of pharmaceutically interesting chiral tetrahydrofurans starting from mannose diacetonide is reported. A 1,4-diol system derived from mannose diacetonide, through a Mitsunobu reaction was stereospecifically cyclized to give chiral tetrahydrofurans. Both the C-1 and C-4 centers of d-mannose are successfully exploited to install the requisite side chains.     

Chiron approach for the synthesis of (1S,2R,5R,7S)-2-hydroxy-exo-brevicomin

(1S,2R,5R,7S)-2-Hydroxy-exo-brevicomin ent-1 was synthesized from 1,2;5,6-di-O-isopropylidene-d-glucose in seven steps. The key reaction in our synthesis is the formation of bicyclic ketal 7 under acid mediated acetal exchange of a 1,2-acetonide of d-glucose derivative 6.     

Heterotricyclodecane XX (+)-(1S, 3S, 6S, 8S)- und (−)-(1R, 3R, 6R, 8R)-2, 7-Dioxa-twista-4,9-dien

(+)-(1S, 3S, 6S, 8S)- and (?)-(1R, 3R, 6R, 8R)-2,7-dioxa-twista-4,9-diene. A synthesis and the determination of the sense of chirality of (+)-(1S, 3S, 6S, 8S)- and (?)-(1R, 3R, 6R, 8R)-2,7-dioxa-twista-4,9-diene ((+)- 5 and (?)- 5 , respectively) is described.     

A Convenient Method for Synthesis of Novel Cyclic Ethers (1R,2R,3R,5S,7S,9R,12R)-3-(t-Butyldimethylsilyl)oxy-7-methoxymethyl-oxy-2,10-dimethyl-12-oxatricyclo [7.2.1.0~(5,12)] dodecane

Coloradocin, a novel macrolide antibiotic from cultures of Actinoplanes coloradoensis1exhibits activity against pathogenic anaerobic and microaerophilic species2. Because itslow toxicity and substantial oral activity3, , as well as its unusual structure5, several 4research groups initiated approaches towards the synthesis of coloradocin6, whichculminated in the synthesis of 18-deoxynargenicin A1 by Kallmerten et al.7. …     

Convenient synthesis of （2S,3R,4R,5S,6R）-2-（3-（4-ethylbenzyl）-4- chlorophenyl）-6-（hydroxymethyl）-tetrahydro- 2H-pyran-3,4,5-triol

A convenient approach for the preparation of （2S,3R,4R,5S,6R）-2-（3-（4-ethylbenzyl）-4-chlorophenyl）-6-（hydroxymethyl）- tetrahydro-2H-pyran-3,4,5-triol I is developed. The target compound via four steps is synthesized from 4-bromo-2-（bromomethyl）- 1-chlorobenzene and the isomers of undesired ortho-products were avoided during the preparation.     

Synthesis from D-glucose of alexine [(1R,2R,3R,7S,8S)-3-hydroxymethyl-1,2,7-trihydroxypyrrolizidine], 3-epialexine and 7-epialexine

A protected 2-azido-2-deoxymannose is a key intermediate in the synthesis of alexine [(1R,2R,3R,7S,8S)-3-hydroxymethyl-1,2,7-trihydroxypyrrolizidine], 3-epialexine and 7-epialexine from D-glucose.     

Stereoselectivity in Reactions of Metal Complexes IV. Asymmetric Synthesis of (2R, 7S, 10R)- and (2R, 7R, 10R)-2, 10-diamino-5, 5, 7-trimethyl-4, 8-diazaundecanenickel (II) by Stereoselective Hydrogenation of (2R, 10R)-2, 10-diamino-5, 5, 7-trimethyl-4, 8-diaza-7-undecenenickel(II)

The catalytic hydrogenation of (2R, 10R)-2, 10-diamino-5, 5, 7-trimethyl-4, 8-diaza-7-undecenenickel(II) yields two products when the reaction is performed in the presence of ethylenediamine, but only one, when ethylenediamine is absent. The stereochemistry of the reaction is discussed and a proposal for the absolute configuration of the two diastereomeric complexes and the free ligands is given on the base of CD.- and NMR.-spectra.     

(1R,2S,5R,8S,9R,10S)-8-甲基-4-氮杂-5-苯基-7-氧杂四环[8.2.1.0~(2,9).0(~4,8)]十三-11-烯-3-酮的合成和晶体结构

为确定内型降冰片烯酰亚胺与甲基格氏试剂反应所得加成产物的结构,合成了标题化合物(C18H19NO2)。其结构通过单晶X-射线衍射分析确定,该晶体属正交晶系,空间群为P212121,a = 6.293(1),b = 14.342(3),c = 16.357(3) 牛琕 = 1476.2(5) ?,Z = 4,Dc = 1.266 g/cm3, (MoKa) = 0.082mm-1,F(000) = 600。晶体结构用直接法解出,最终的偏离因子为R = 0.0535,wR = 0.988。由此晶体结构可确定加成产物为标题化合物,并由1H-NMR数据推测另一加成产物的结构。