213595-50-7

Upstream product

• 70-55-3 toluene-4-sulfonamide 
• 100-52-7 benzaldehyde 
• 774-48-1 (diethoxymethyl)benzene 
• 172794-67-1 (4R,5R)-2-(2-Bromo-benzyl)-4,5-bis-(1-methoxy-1-methyl-ethyl)-[1,3]dioxolane 
• 98-59-9 p-toluenesulfonyl chloride 
• 51608-60-7 phenyl N-tosyl imine 
• 1613-90-7 4-methoxy-N-[(E)-phenylmethylidene]aniline 

Downstream Products

• 213595-53-0 (R)-(-)-2-<<(4R,5R)-4,5-bis(2-methoxypropan-2-yl)-1,3-dioxolan-2-yl>methyl>benzhydrylamine 
• 99267-98-8 (2R,3R)-1,4-dimethoxy-1,1,4,4-tetramethyl-2,3-butanediol 
• 220936-55-0 (R)-(+)-2-(4-methylphenylsulfonyl)-1-phenyl-1,2-dihydroisoquinoline 
• 213686-55-6 (-)-benzyl N-<(αR)-2-<<(4R,5R)-4,5-bis(2-methoxypropan-2-yl)-1,3-dioxolan-2-yl>methyl>benzhydryl>carbamat 
• 180272-45-1 (R)-(-)-1-phenyl-1,2,3,4-tetrahydroisoquinoline 
• 207615-49-4 (R)-(+)-benzyl 1-phenyl-1,2-dihydroisoquinoline-2-carboxylate 
• 220936-57-2 (R)-(+)-2-(4-methylphenylsulfonyl)-1-phenyl-1,2,3,4-tetrahydroisoquinoline 

Relevant academic research and scientific papers

Diastereoselective addition of chiral (2-lithiophenyl)acetaldehyde acetals to various imines as key step in the asymmetric synthesis of 1- aryltetrahydroisoquinolines, part 4

A novel asymmetric synthesis of 1-aryl-1,2,3,4-tetrahydroisoquinolines has been developed. The key step in this synthesis is the diastereoselective addition of homochiral (2-lithiophenyl)acetaldehyde acetals to the sulfonylimine 25 and to the arylimines 28 and 31. The best diastereoselectivity is obtained by addition of the bis(2-methoxypropan-2- yl)-substituted 1,3-dioxolane 6e to benzylidene-p-anisidine (31) with an HPLC-determined diastereomeric ratio 32c/33c = 92.1:7.9. The N-tosyl and the N-(4-methoxyphenyl) groups of the addition products 26d, 27d, 32c, and 33c are cleaved with sodium in liquid ammonia and ammonium cerium(IV) nitrate, respectively, to yield the primary amines 35 and 36. The acid-catalysed cyclization of the sulfonamides 26d and 27d and the carbamates 37 and 38, prepared from 35 and 36, leads to the enantiomerically pure dihydroisoquinolines 40 and 41, respectively. During the cyclization of the sulfonamides 26d, 27d and the carbamates 37, 38 the chiral auxiliary - the diol 39 - is cleaved unchanged and can be recovered in good yields.

Investigation of the diastereoselectivity during the addition of an enantiomerically pure (2-lithiophenyl)acetaldehyde acetal to various imines

The diastereoselectivity during the addition of the homochiral (2-lithiophenyl)acetaldehyde acetal 1b to various imine components was investigated. The diastereoselectivity could be raised to 84.2% de by addition of 1b to benzylidenanisidine 2h. Removal of the tosyl and the p-methoxyphenyl protective groups of 3c, 4c and 3h/4h succeeded with sodium in liquid ammonia and ammonium cerium(IV) nitrate, respectively, to yield the enantiopure benzhydrylamines 5 and 6.