- Asymmetric total synthesis of (?)-javaberine A and (?)-epi-javaberine A based on catalytic intramolecular hydroamination of N-methyl-2-(2-styrylaryl)ethylamine
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Asymmetric total synthesis of (?)-javaberine A and its epimer was achieved by utilizing two methods for isoquinoline synthesis, asymmetric hydroamination of N-methyl-2-(2-styrylaryl)ethylamine and Bischler-Napieralski cyclization. Intramolecular asymmetric hydroamination of N-methyl aminoalkene 4 was catalyzed by lithium amide–chiral bisoxazoline to give tetrahydroisoquinoline (S)-laudanosine with good enantioselectivity in excellent yield. N-Demethylation of (S)-laudanosine was accomplished by Polonovski-type reaction to give (S)-norlaudanosine. Condensation of (S)-norlaudanosine with homoveratric acid, and subsequent Bischler-Napieralski cyclization, LiAlH4 reduction, and O-demethylation furnished (8R,14S)-(?)-javaberine A, corresponding to antipode of natural javaberine A. (8S,14S)-(?)-Javaberine A, which corresponds to C14-epimer of natural javaberine A, was also successfully synthesized.
- Uenishi, Saho,Kakigi, Rina,Hideshima, Kumiko,Miyawaki, Akari,Matsuoka, Junpei,Ogata, Tokutaro,Tomioka, Kiyoshi,Yamamoto, Yasutomo
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- Biosynthesis of plant tetrahydroisoquinoline alkaloids through an imine reductase route
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Herein, we report a biocatalytic approach to synthesize plant tetrahydroisoquinoline alkaloids (THIQAs) from dihydroisoquinoline (DHIQ) precursors using imine reductases and N-methyltransferase (NMT). The imine reductase IR45 was engineered to significant
- Yang, Lu,Zhu, Jinmei,Sun, Chenghai,Deng, Zixin,Qu, Xudong
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p. 364 - 371
(2020/01/21)
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- Synthesis of Tetrahydroisoquinoline Alkaloids and Related Compounds through the Alkylation of Anodically Prepared α-Amino Nitriles
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α-Amino nitrile 2a was conveniently prepared in two individual steps from chiral hexafluorophosphate salt isoquinolinium (-)-8b including anodic cyanation as an efficient means to activate the sp3 C1-H bond of the THIQ nucleus. The lithiation o
- Benmekhbi, Lotfi,Louafi, Fadila,Roisnel, Thierry,Hurvois, Jean-Pierre
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p. 6721 - 6739
(2016/08/16)
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- Efficient and Practical Syntheses of Enantiomerically Pure (S)-(-)-Norcryptostyline I, (S)-(-)-Norcryptostyline II, (R)-(+)-Salsolidine and (S)-(-)-Norlaudanosine via a Resolution-Racemization Method
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Four racemic tetrahydroisoquinolines (RS)-(±)-1-4 were prepared from homoveratrylamine via amidation, Bischler-Napieralski reaction and the subsequent reduction. The enantiomerically pure tetrahydroisoquinolines (S)- (-)-norcryptostyline I [(S)-(-)-1], (S)-(-)-norcryptostyline II [(S)-(-)-2], (R)-(+)-salsolidine [(R)-(+)-3] and (S)-(-)-norlaudanosine [(S)-(-)-4] were then obtained in 45%, 40%, 41% and 38% yields, respectively, via resolution of the racemic compounds (RS)-(±)-1-4 with half equivalent of chiral acids. In addition, the enantiomerically enriched compounds (R)-(+)-1, (R)-(+)-2, (S)-(-)-3 and (R)-(+)-4 from the mother liquors were efficiently racemized via a one-pot redox method in almost quantitative yields.
- Zhu, Ruiheng,Xu, Zhangli,Ding, Wei,Liu, Shiling,Shi, Xiaoxin,Lu, Xia
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p. 1039 - 1048
(2016/02/18)
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- Enantioselective synthesis of tetrahydroprotoberberines and bisbenzylisoquinoline alkaloids from a deprotonated α-aminonitrile
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Under controlled conditions, 6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline- 1-carbonitrile can be quantitatively deprotonated in the α-position. Its alkylation directly furnishes 3,4-dihydroisoquinolines which can serve as starting materials for the preparation of various alkaloids. Here, the preparation of the benzylisoquinolines (+)-laudanidine, (+)-armepavine, and (+)-laudanosine as well as the tetrahydroprotoberberines ( - )-corytenchine and ( - )-tetrahydropseudoepiberberine using Noyori's asymmetric transfer hydrogenation are described. The dimeric alkaloids (+)-O-methylthalibrine and (+)-tetramethylmagnolamine were obtained from nonracemic precursors in Ullmann diaryl ether syntheses.
- Blank, Nancy,Opatz, Till
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p. 9777 - 9784
(2012/01/30)
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- Asymmetric synthesis of (S)-(-)-xylopinine. Use of the sulfinyl group as an ipso director in aromatic SE
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Optically pure (S)-(-)-xylopinine 2 was prepared in three steps in 52% overall yield. Thus, condensation of the carbanion derived from (S)-4 with the (S)-(E)-sulfinylimine 5 gave a 2:1 mixture of tetrahydroisoquinolines 6a and 6b, differing only in configuration at sulfur. N-Desulfinylation of this mixture gave the diastereomeric sulfoxides which, without separation, were converted into (S)-(-)-xylopinine (2) with loss of the sulfinyl moieties under Pictet-Spengler conditions. This unprecedented ipso electrophilic substitution of a sulfinyl group may have synthetic implications beyond that described in this work.
- Mastranzo, Virginia M.,Yuste, Francisco,Ortiz, Benjamin,Sanchez-Obregon, Ruben,Toscano, Ruben A.,Garcia Ruano, Jose L.
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p. 5036 - 5041
(2011/08/06)
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- Synthesis of (-)-(S)-norlaudanosine, (+)-(R)-O,O-dimethylcoclaurine, and (+)-(R)-salsolidine by alkylation of an α-aminonitrile
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A short asymmetric synthesis of 1-substituted 1,2,3,4- tetrahydroisoquinoline alkaloids by deprotonation of an unprotected α-aminonitrile and alkylation of the resulting carbanion followed by spontaneous elimination of HCN and asymmetric reduction is described. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
- Werner, Frank,Blank, Nancy,Opatz, Till
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p. 3911 - 3915
(2008/02/13)
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- Enantioselective synthesis of (+)-(S)-laudanosine and (-)-(S)-xylopinine
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The study presents a new pathway for the enantioselective synthesis of benzylisoquinoline alkaloids. The key steps of the synthesis of (+)-(S)-laudanosine (1) and (-)-(S)-xylopinine (2) are a Sonogashira coupling that builds up the C1-C8a bond of the benzylisoquinoline skeleton, an intramolecular Ti-catalyzed hydroamination of an alkyne, and a subsequent enantioselective imine reduction according to Noyori's protocol.
- Mujahidin, Didin,Doye, Sven
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p. 2689 - 2693
(2007/10/03)
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- Asymmetric reduction of prochiral cyclic imines to alkaloid derivatives by novel asymmetric reducing reagent in THF or under solid-state conditions
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Asymmetric reductions of prochiral cyclic imines were studied using chiral nonracemic sodium acyloxy borohydride 2. The chiral nonracemic reducing agent 2 has been easily prepared by the reaction of NaBH4 with N,N- phthaloyl amino acid 1 in THF
- Hajipour,Hantehzadeh
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p. 8475 - 8478
(2007/10/03)
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- Enantioselective catalytic reduction of dihydroisoquinoline derivatives
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Thiazazincolidine complexes, 2, were shown to be excellent catalysts for enantioselective reduction of dihydroisoquinolines 1 with BH3 · THF to the corresponding amines in good ee.
- Kang, Jahyo,Kim, Jin Bum,Cho, Kwi Hyung,Cho, Byung Tae
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p. 657 - 660
(2007/10/03)
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- Asymmetric synthesis of (s)-norlaudanosine and (s)-tetrahydrohomopapaverine by catalytic asymmetric hydrogenation with chiral diphosphine-iridium(i)-phthalimide complex catalysts
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Optically active 1,2,3,4-tetrahydroisoquinoline alkaloids, (S)-norlaudanosine and (S)-tetrahydrohomopapaverine, were prepared by catalytic asymmetric hydrogenation of 1-substituted 3,4-dihydro-6,7-dimethoxyisoquinolines with 1 mol % of an iridium(I) compl
- Morimoto, Toshiaki,Suzuki, Naoaki,Achiwa, Kazuo
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p. 2557 - 2560
(2007/10/03)
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- A novel asymmetric route to the 1,3-disubstituted tetrahydroisoquinoline, (-)-argemonine
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Chiral bicyclic lactam 13 was converted to the natural product (-)-argemonine 9 in six steps. This novel route to argemonine represents a general strategy for the preparation of chiral 1,3-disubstituted tetrahydroisoquinolines.
- Munchhof, Michael J.,Meyers
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p. 4607 - 4610
(2007/10/03)
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- General asymmetric synthesis of isoquinoline alkaloids. Enantioselective hydrogenation of enamides catalyzed by BINAP-ruthenium(II) complexes
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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.
- Kitamura,Hsiao,Ohta,Tsukamoto,Ohta,Takaya,Noyori
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p. 297 - 310
(2007/10/02)
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- Asymmetric synthesis of 1-benzyltetrahydroisoquinolines using chiral oxazolo[2,3-a]tetrahydroisoquinolines
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A novel synthetic route to enantiomerically pure 1-benzyltetrahydroisoquinolines (1) was developed via the reaction of oxazolo[2,3-a]tetrahydroisoquinoline (5) with benzyltriisopropoxytitanium compounds (10). This method was applied to the synthesis of (S)-trimetoquinol (1c; a bronchodilator).
- Hashigaki,Kan,Qais,Takeuchi,Yamato
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p. 1126 - 1131
(2007/10/02)
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- Stereoselective Nucleophilic Additions to the Carbon-Nitrogen Double Bond. 2. Chiral Iminium Ions Derived from "Second Generation" Chiral Amines
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"Second generation" chiral amines (1S)-(-)-1-(2-chlorophenyl)ethylamine (4) and (1S)-(-)-1-(2,6-dichlorophenyl)ethylamine (5) have been prepared from commercially available (S)-(-)-α-phenethylamine.These chiral reagents have been incorporated into chiral
- Polniaszek, Richard P.,Kaufman, Craig R.
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p. 4859 - 4863
(2007/10/02)
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- STEREOSELECTIVE REDUCTIONS OF CHIRAL IMINUM IONS.
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Chiral iminium ions derived from α-phenethylamine have been reduced stereoselectively with NaBH4.Diastereoselection of reduction ranged from 88:12 to 94:6.The sense of asymmetric induction has been unambiguously assigned by correlation of reduction produc
- Polniaszek, Richard P.,McKee, Julia A.
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p. 4511 - 4514
(2007/10/02)
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