79328-86-2

Upstream product

• 110-86-1 pyridine 
• 1885-14-9 phenyl chloroformate 
• 86801-40-3 1-phenoxycarbonylpyridinium chloride 

Downstream Products

• 79328-92-0 (1R,4R,6S)-6-(1-Benzenesulfonyl-1H-indol-2-yl)-2-aza-bicyclo[2.2.2]oct-7-ene-2,6-dicarboxylic acid 2-tert-butyl ester 6-methyl ester 
• 79328-87-3 (1S,4S,6S)-6-(1-Benzenesulfonyl-1H-indol-2-yl)-2-aza-bicyclo[2.2.2]oct-7-ene-2,6-dicarboxylic acid 2-tert-butyl ester 6-methyl ester 
• 105335-77-1 5-formyl-1-(phenoxycarbonyl)-1,2-dihydropyridine 

Relevant academic research and scientific papers

Synthesis of bicyclic tetrahydropyridine enamides and enecarbamates by hetero-Cope rearrangement of nitroso cycloadducts

[Figure not available: see fulltext.] The hetero-Cope rearrangement reactions of inverse carbamate and amide nitroso Diels–Alder cycloadducts with 1,2-dihydropyridines to give novel tetrahydropyridine enamides and enecarbamates have been studied in detail

Electron transfer from hexameric copper hydrides

The octahedral core of 84-electron LCuH hexamers does not dissociate appreciably in solution, although their hydride ligands undergo rapid intramolecular rearrangement. The single-electron transfer proposed as an initial step in the reaction of these hexamers with certain substrates has been observed by stopped-flow techniques when [(Ph3P)CuH]6 is treated with a pyridinium cation. The same radical cation has been prepared by the oxidation of [(Ph3P)CuH]6 with Cp* 2Fe+ and its reversible formation observed by cyclic voltammetry; its UV-vis spectrum has been confirmed by spectroelectrochemistry. The 48-electron trimer [(dppbz)CuH]3 has been prepared by use of the chelating ligand 1,2-bis(diphenylphosphino)benzene (dppbz).

Synthesis, electrochemistry, and reactivity of new iridium(III) and rhodium(III) hydrides

Two new iridium hydride complexes, Cp*Ir(2-phenylpyridine)H (Cp* = pentamethylcyclopentadienyl) and Cp*Ir(benzo[h]quinoline)H, and their rhodium analogues Cp*Rh(2-phenylpyridine)H and Cp*Rh(benzo[h]quinoline)H have been prepared from the corresponding chl

Substituted Dihydropyridine Synthesis by Dearomatization of Pyridines

Dearomatization is an effective method to transform readily available N-heterocycles into partially saturated motifs. Manipulation of dihydro-derivatives holds great potential and provides access to a variety of semi-saturated N-heterocyclic building blocks. However, current strategies are limited in scope and the use of sensitive reagents restricts the applicability in synthetic laboratories. Herein, we report the synthesis of a broad variety of N-substituted 1,4- and 1,2-dihydropyridines by very mild and selective reduction with amine borane for the first time.

Enantioselective Synthesis of Chiral Piperidines via the Stepwise Dearomatization/Borylation of Pyridines

We have developed a novel approach for the synthesis of enantioenriched 3-boryl-tetrahydropyridines via the Cu(I)-catalyzed regio-, diastereo-, and enantioselective protoborylation of 1,2-dihydropyridines, which were obtained by the partial reduction of the pyridine derivatives. This dearomatization/enantioselective borylation stepwise strategy provides facile access to chiral piperidines together with the stereospecific transformation of a stereogenic C-B bond from readily available starting materials. Furthermore, the utility of this method is demonstrated for the concise synthesis of the antidepressant drug (-)-paroxetine. A theoretical study of the reaction mechanism is also described.

Boron Tribromide-Assisted Chiral Phosphoric Acid Catalyst for a Highly Enantioselective Diels-Alder Reaction of 1,2-Dihydropyridines

BBr3-chiral phosphoric acid complexes are highly effective and practical Lewis acid-assisted Bronsted acid (LBA) catalysts for promoting the enantioselective Diels-Alder (DA) reaction of α-substituted acroleins and α-CF3 acrylate. In particular, the DA reaction of α-substituted acroleins with 1,2-dihydropyridines gave the corresponding optically active isoquinuclidines with high enantioselectivities. Moreover, transformations to the key intermediates of indole alkaloids, catharanthine and allocatharanthine, are demonstrated.

Asymmetric synthesis of isoquinuclidines by Diels-Alder reaction of 1,2-dihydropyridine utilizing a chiral Lewis acid catalyst

The chiral isoquinuclidine derivative, 2-azabicyclo[2.2.2]octane ring system, endo-(7R)-3 was obtained in good yield with excellent diastereoselectivity (up to 92% de) by Diels-Alder reaction of 1-(phenoxycarbonyl)-1,2-dihydropyridine 1 with N-acryloyl-(4S)-4- benzyloxazolidin-2-one (4S)-2 using titanium-(2R,3R)-TADDOLate 4 as a chiral Lewis acid catalyst in toluene at 0 °C. On the other hand, endo-(7S)-3 was obtained in good yield with excellent diastereoselectivity (up to 97% de) by Diels-Alder reaction of 1 with (4R)-2 using Cu(OTf)2/(4S,4′S)- bis(oxazoline) catalyst 8 as a chiral Lewis acid catalyst in dichloromethane at 0 °C. In these reactions, the choice of solvent and the combination of titanium-(2R,3R)-TADDOLate 4 {or Cu(II)/(4S,4′S)-bis(oxazoline) 8} and dienophile (4S)-2 {or (4R)-2} are very important. The stereochemistry of endo-(7R)-3 has been established to be (1R,4S,7R) and the reaction mechanism is proposed.

Highly enantioselective synthesis of isoquinuclidine by diels-alder reaction of 1,2-dihydropyridine utilizing chiral bisoxazoline-Cu(II) complex

The enantioselective Diels-Alder (D-A) reaction between N-phenoxycarbonyl- or N-benzyloxycarbonyl-1,2-dihydropyridine (1a or 1b) and N(2)-acryloyl-N(1)-(1- naphthylmethyl)-5,5-dimethylpyrazolidin-3-one (2b) using (S,S)-bisoxazoline- Cu(II) catalyst (A, B, C or D) has been investigated. Utilizing (S,S)-t-Bu-bisoxazoline-Cu(II) catalyst C, the D-A reaction of 1a and 2 afforded the endo-(7S)-isoquinuclidines (3, 4 or 5) in good chemical yields with high enantioselectivity (up to 99% e.e.).

An efficient synthesis of chiral isoquinuclidines by Diels - Alder reaction using Lewis acid catalyst

The Diels-Alder reaction of 1,2-dihydropyridine derivatives (1-phenoxycarbonyl-1,2-dihydropyridine 1 or 1-methoxycarbonyl-1,2- dihydropyridine 4) with N-acryloyl (1S)-2,10-camphorsultam (1S)-2 {or N-acryloyl (1R)-2,10-camphorsultam (1R)-2} in the presence of Lewis acid, such as titanium tetrachloride, zirconium tetrachloride, and hafnium tetrachloride afforded the endo-cycloaddition product, 2-azabicyclo[2.2.2]octane derivatives in good yields with excellent diastereoselectivity. The absolute stereochemistry assignment of the endo-cycloaddition product (1S)-5a starting from N-acryloyl (1S)-2,10-camphorsultam (1S)-2 has been established to be (1S,4R,7S) and the reaction mechanism was proposed.

Using a two-step hydride transfer to achieve 1,4-reduction in the catalytic hydrogenation of an Acyl pyridinium cation

(Chemical Equation Presented) The stoichiometric reduction of N-carbophenoxypyridinium tetraphenylborate (6) by CpRu(P-P)H (Cp = η5-cyclopentadienyl; P-P = dppe, 1,2-bis(diphenylphosphino) ethane, or dppf, 1,1′-bis(diphenylphosphino)ferrocene), and Cp*Ru(P-P)H (Cp* = η5-pentamethylcyclopentadienyl; P-P = dppe) gives mixtures of 1,2- and 1,4-dihydropyridines. The stoichiometric reduction of 6 by Cp*Ru(dppf)H (5) gives only the 1,4-dihydropyridine, and 5 catalyzes the exclusive formation of the 1,4-dihydropyridine from 6, H 2, and 2,2,6,6-tetramethylpiperidine. In the stoichiometric reductions, the ratio of 1,4 to 1,2 product increases as the Ru hydrides become better one-electron reductants, suggesting that the 1,4 product arises from a two-step (e-/H?) hydride transfer. Calculations at the UB3LYP/6-311++G(3df,3pd)//UB3LYP/6-31G* level support this hypothesis, indicating that the spin density in the N-carbophenoxypyridinium radical (13) resides primarily at C4, while the positive charge in 6 resides primarily at C2 and C6. The isomeric dihydropyridines thus result from the operation of different mechanisms: the 1,2 product from a single-step H- transfer and the 1,4 product from a two-step (e-/H?) transfer.