116172-12-4

Upstream product

• 497-02-9 (E)-2-methyl-2-buten-1-ol 
• 60355-99-9 2-<(4-Methoxyphenyl)methylene>-3,4-dimethyl-5,6-dihydropyridine hydrochloride 
• 60355-98-8 N-(3'-methyl-3'-pentenyl)-4-methoxyphenylacetamide 
• 116172-15-7 (E)-3-methyl-3-pentenylamine 
• 116172-14-6 (E)-3-methyl-3-pentenenitrile 
• 80-59-1 Tiglic acid 
• 116172-10-2 (Z)-1-Formyl-2-<(4-methoxyphenyl)methylene>-3,4-dimethyl-1,2,5,6-tetrahydropyridine 

Downstream Products

• 116172-13-5 (R)-2-(4-methoxybenzyl)-3,4-dimethyl-1,2,5,6-tetrahydropyridine 

Relevant academic research and scientific papers

General asymmetric synthesis of isoquinoline alkaloids. Enantioselective hydrogenation of enamides catalyzed by BINAP-ruthenium(II) complexes

In the presence of a small amount of RuX2[(R)- or (S)-BINAP] (X = anionic ligand) a wide range of (Z)-2-acyl-1-benzylidene-1,2,3,4- tetrahydroisoquinolines are hydrogenated to give the saturated products in nearly quantitative yields and in high (up to 100%) optical yields. The enamide substrates are selectively prepared by N-acylation of the corresponding 1-benzylated 3,4-dihydroisoquinolines under suitable acylation conditions; some crystalline materials having low solubility are obtained by a second-order Z/E stereomutation technique utilizing the double-bond photolability and lattice energy effects. This asymmetric hydrogenation sets the key stereogenic center in a predictable manner, either R or S flexibly, at the C(1) position of the benzylated tetrahydroisoquinolines. The chiral products are converted by standard functional group modification to tetrahydropapaverine, laudanosine, tretoquinol, norreticuline, etc. Hydrogenation of the simple 1-methylene substrate is used for synthesis of salsolidine. This enantioselective hydrogenation is applied to the synthesis of morphine and its artificial analogues such as morphinans and benzomorphans of either chirality. A mnemonic device is presented for predicting the reactivity and enantiofacial selection of the BINAP-Ru catalyzed hydrogenation. Reaction with BINAP-Rh catalyst proceeds with a lower enantioselectivity and an opposite sense of asymmetric induction.

GENERAL ASYMMETRIC SYNTHESIS OF BENZOMORPHANS AND MORPHINANS VIA ENANTIOSELECTIVE HYDROGENATION

A variety of optically active benzomorphans including metazocine and pentazocine as well as dextromethorphan, a morphinan, are obtainable by using the BINAP-ruthenium(II) catalyzed enantioselective hydrogenation as key operation.