581095-83-2

Upstream product

• 542-92-7 cyclopenta-1,3-diene 
• 391928-90-8 (2S)-2-benzyloxy-2H-pyran-3-(6H)-one 
• 87-72-9 D-Xylose 
• 108646-05-5 (3S,4R,5R)-tetrahydro-2H-pyran-2,3,4,5-tetrayl tetraacetate 
• 113889-50-2 (3S,4R,5R)-2-bromotetrahydro-2H-pyran-3,4,5-triyl triacetate 
• 14125-76-9 1,5-anhydro-2,3,4-tri-O-acetyl-D-threo-pent-1-enitol 
• 28697-53-2 D-arabinopyranose 
• 30694-66-7 2,3,4-tri-O-acetyl-1,5-anhydro-D-erythro-pent-1-enitol 
• 62446-93-9 1,2,3,4-tetra-O-acetyl-D-xylopyranose 
• 50837-92-8 2,3,4-tri-O-acetyl-D-xylopyranosyl bromide 

Downstream Products

• 705945-52-4 (3S,4S,4aS,5R,8S,8aR)-3-benzyloxy-4-hydroxy-3,4,4a,5,8,8a-hexahydro-5,8-methano-1H-2-benzopyran 

Relevant academic research and scientific papers

Reactions of Diels-Alder adducts of a sugar-derived dihydropyranone leading to fused polycyclic compounds

Manipulation of the ketone and alkene functions of cycloadducts 2, 3, and 4, derived from optically active (ee >86%) (S)-2-benzyl-2H-pyran-3(6H)-one (1), led to polycyclic systems having three or four fused rings. Reduction of the carbonyl group of the butadiene adduct (2) took place with low facial selectivity affording the alcohols 5 and 6 in 1:1.4 ratio. In contrast, a higher diastereoselection was observed for the reduction of the carbonyl of the cyclopentadiene adducts 3 and 4 to give the endo alcohols 10 and 13, respectively. The epoxidation of 6 showed low facial selectivity in the formation 7 and 8, whereas epoxidation of 10 and 13 took place from the exo face of the norbornene system to give spontaneously the polycyclic alcohols 11 and 14 by opening of the epoxide by intramolecular attack of the hydroxyl group of the pyranoid ring. Similarly, addition of iodine to 10 led to the polycyclic iodide 12.

Stereocontrolled Diels - Alder cycloadditions of sugar-derived dihydropyranones with dienes

2-Acetoxy-3,4-di-O-acetyl-D-arabinal (6), similar to its D-xylo analogue 4, reacted with benzyl alcohol by the tin(IV) chloride-promoted glycosylation to produce optically active (S)-2-benzyloxy-2H-pyran-3(6H)-one (8a). The L-arabinal derivative (5) gave 9a, the dihydropyranone enantiomer of 8a. These results indicated that the configuration of the C-4 stereocenter in the starting glycal defines the configuration of the new chiral center in the resulting dihydropyranone. The influence of other catalysts (BF3 or iodine) employed for the glycosylation on the optical purity of the dihydropyranone was studied. Enantiomerically pure dihydropyranones 8b and 9c were obtained using chiral alcohols ((R)- and (S)-2-octanol, respectively) as glycosylating agents. Compounds 8a,b and 9a,c proved to be reactive dienophiles in thermal and Lewis acid-promoted Diels - Alder reactions. The addition of 2,3-dimethylbutadiene, cyclopentadiene, and 1,3-cyclohexadiene to the β-pyranones 8a,b led to the corresponding adducts 10a,b, 12a,b, and 16a,b as major products. Enantiomeric cycloadducts were synthesized from the α-pyranones 9a,c. The main products were formed by highly facial-diastereoselective addition of dienes to the pyranone ring, guided by the sterical hindrance of the alkoxy substituent of the C-2 stereocenter. As cycloadditions with cycloalkadienes were also highly endo diastereoselective, these reactions gave access to pure tetrahydrobenzopyranones that carry a multitude of stereogenic centers installed in a predictable way.