22248-28-8

Upstream product

• 61171-98-0 (+/-)-Di-O-methylagatharesinol 
• 135966-02-8 3-(2,2-Dimethyl-[1,3]dioxolan-4-yl)-1,3-bis-(4-methoxy-phenyl)-propan-1-ol 
• 105213-31-8 (E)-methyl 4-(4-methoxyphenyl)-2-oxobut-3-enoate 
• 2186-92-7 p-Anisaldehyde dimethyl acetal 
• 637-69-4 4-Methoxystyrene 

Relevant academic research and scientific papers

Lignans.19. Total synthesis of (-)-O-dimethylsugiresinol, involving asymmetric [4+2] heterocycloaddition of a styrene with a benzylidenepyruvic ester of an α-O-silyl derivative of (D)-erythronolactone

α-O-t-Butyldiphenylsilyl-(D)-erythronolactone [(+)-25] (a new chiral vector) was esterified with 4-methoxybenzylidene pyruvic acid (19). Eu(fod)3 catalyzed [4+2] heterocycloaddition of the latter 1-oxabutadiene with 4- methoxystyrene (as the dienophile), afforded high yields of the endo adduct 23c with 95/5 diastereofacial ratio. Five further steps led to enantiomerically pure natural (-)-O-dimethylsugiresinol (-)-2 in 12% overall yield from the acid 19.

Enantioselective total synthesis of the di-O-methyl ethers of (-)-agatharesinol, (+)-hinokiresinol and (-)-sugiresinol, characteristic norlignans of Coniferae

Facile enantioselective syntheses of the di-O-methyl ethers of the norlignans, (-)-agatharesinol (-)-1a, (+)-hinokiresinol (+)-2a and (-)-sugiresinol (-)-3a are described. Grignard addition of vinylmagnesium bromide to an aldimine (-)-13, prepared from the tert-butyl ester 11 and 4-methoxycinnamaldehyde 12, afforded a homochiral vinyl aldehyde, (-)-3-(4-methoxyphenyl)pent-4-enal (-)-14 in > 95% ee, which was converted into a diastereoisomeric mixture of 1,3-bis(4-methoxyphenyl)pent-4-en-1-ols (3R)-6 by a second Grignard reaction with 4-methoxyphenylmagnesium bromide. Sharpless' asymmetric dihydroxylation of the vinyl alcohols (3R)-6 proceeded diastereoselectively to give the triol of desired relative stereochemistry (2S,3S)-7. This, upon dehydration, afforded (-)-di-O-methylsugiresinol (-)-3b, the subsequent acid-catalysed cyclization of which gave (-)-di-O-methyl agatharesinol (-)-1b. (+)-Di-O-methylhinokiresinol (+)-2b was readily obtained by the dehydration of the vinyl alcohols (3R)-6.