Asymmetric Morita-Baylis-Hillman reaction catalyzed by isophoronediamine-derived bis(thio)urea organocatalysts

New and improved bis(thio)urea catalysts were synthesized from isophoronediamine (IPDA) and tested in the Morita-Baylis-Hillman reaction. The best results were achieved in the reaction of 2-cyclohexen-1-one with cyclohexanecarbaldehyde, using the catalyst depicted above, in combination with a novel base (N,N,N',N'-tetramethylisophoronediamine, TMIPDA) in toluene. The desired Morita-Baylis-Hillman product was obtained in 75% yield and 96% ee.     

Asymmetric Morita-Baylis-Hillman reactions of 2-cyclohexen-1-one catalyzed by chiral biaryl-based bis(thiourea) organocatalysts

Newly-developed bis(thiourea) 1d was found to be an efficient organocatalyst for the Morita-Baylis-Hillman reaction. High enantioselectivities were obtained in the reaction of 2-cyclohexen-1-one with both aromatic aldehydes (up to 84% ee) and aliphatic aldehydes (up to 96% ee).     

An efficient and simple Morita-Baylis-Hillman reaction based on the N-methylpyrrolidine-Ba(OH)2 catalytic system

By using of precise catalytic amount of N-methylpyrrolidine (5 mol %) and Ba(OH)₂ (1.5 mol %) in H₂O/CH₃OH 5/1 or CH₃OH/CH₂Cl₂ 3/1 solvent mixtures at T=0 °C a Morita-Baylis-Hillman derivatives could be obtained in good to excellent yield from 2-cyclopenten-1-one, 2-cyclohexen-1-one and formaldehyde and diverse aryl aldehydes after suitable reaction time.     

Synthesis of decahydrophenanthridine-1,7-dione and hexahydroisoquinol-8-one derivatives in the reaction of 2-acetyl-2-cyclohexene-1-ones with conjugated enaminocarbonyl compounds

Derivatives of decahydrophenanthridine-1,7-dione were obtained by the reaction of 2-acetyl-2-cyclohexen-1-ones with enamines of cyclic -diketones (dihydroresorcinol, dimedone). Derivatives of hexahydroisoquinol-8-one having electron-acceptor substituents at the 4-position were obtained by the reaction of 2-acetyl-5,5-dimethyl-2-cyclohexen-1-one with acyclic enaminocarbonyl compounds. The reaction mechanism is discussed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 66–71, January, 1990.     

SYNTHESIS AND CATALYTIC PROPERTY OF POLYSTYRENE SUPPORTED GLUTAMIC ACID SCHIFF BASE COMPLEX OF Mn(Ⅱ)IN AEROBIC OXIDATION OF CYCLOHEXENE

The polystyrene supported glutamic acid Schiff base complex of Mn (Ⅱ) (PS-Sal-Glue-Mn) was prepared with chloromethylated styrene polymer beads,2,4-dihydroxybenzaldehyde, L-glutamic acid and manganese (Ⅱ) acetate tetrahyrate. The polymeric ligand and the complex were characterized by FT-IR, small area X-ray photoelectron spectroscopy (XPS) and ICP-AES. In the presence of the manganese complex, cyclohexene (1) was effectively oxidized by molecular oxygen without reductant. The major products of the reaction were 2-cyclohexen-1-ol (2), 2-cyclohexen-1-one (3) and 2-cyclohexen-1- hydroperoxide (4), which was different with typical oxidation of cyclohexene. The influence of reaction temperature and additive for oxidation had been studied. The selectivity of 2-cyclohexen-1-hydroperoxide varied with reaction time and different additives. The mechanism of cyclohexene oxidation had also been discussed.     

SYNTHESIS AND CATALYTIC PROPERTY OF POLYSTYRENE SUPPORTED PHENYLALANINE SCHIFF BASE COMPLEX OF Mn(Ⅱ) IN AEROBIC OXIDATION OF CYCLOHEXENE

1. INTRODUCTION The partial oxidation of alkenes (forming acids, aldehydes and alcohols) is of considerable interest to the chemical industry. In most cases, more than one oxygenated product is formed from a given starting material and all products are susceptible to complete oxidation to carbon dioxide and water [1]. As mimetic oxygen carrier or oxidation catalyst, metalloporphyrins have been widly studied [2~7]. Among the non-porphyrin systems, the manganese complexes of Schiff base are…     

SYNTHESIS AND CATALYTIC PROPERTY OF POLYSTYRENE SUPPORTED PHENYLALANINE SCHIFF BASE COMPLEX OF Mn（Ⅱ） IN AEROBIC OXIDATION OF CYCLOHEXENE

The polystyrene supported phenylalanine Schiff base complex of Mn(Ⅱ)(PS-Sal-Phe-Mn)was prepared with chloromethylated styrene polymer beads, 2,4-dihydroxybenzaldehyde,L-phenylalanine and manganese(Ⅱ)acetate tetrahyrate., The polymeric ligand and the complex were characterized by FT-IR,, small area X-ray photoelectron spectroscopy(XPS), and ICP-AES. In the presence of the manganese complex, cyclohexene(1)was effectively oxidized by molecular oxygen without reductant. The major products of the reaction were 2-cyclohexen-1-ol(2),2-cyclohexen-1-one(3)and 2-cyclohexen-1- hydroperoxide(4), which was different with typical oxidation of cyclohexene. The influence of reaction temperature and additive for oxidation had been studied. The selectivity of 2-cyclohexen-l-hydroperoxide varied with reaction time and different additives. The mechanism of cyclohexene oxidation had also been discussed.     

Total synthesis of (+)-acanthodoral by the use of a Pd-catalyzed metal-ene reaction and a nonreductive 5-exo-acyl radical cyclization

[reaction: see text] The first total synthesis of the antibiotic acanthodoral (1) has been achieved from 3-methyl-2-cyclohexen-1-one in 19 steps in 2.1% overall yield. The synthesis features the use of a Pd-ene reaction in the presence of CO to form the endocyclic alkene 8, a nonreductive acyl radical cyclization reaction, and a ring contraction reaction by the Wolff rearrangement. (+)-Acanthodoral has also been synthesized starting from (+)-S-2,2-dimethyl-6-methylenecyclohexanecarboxylic acid.     

Synthesis of phenyl-substituted derivatives of decahydrophenanthridine-1, 7-dione and hexahydro-8-isoquinolone

2-Bromo-2-aroylcydohexan-1-ones were prepared by bromination of 2-aroylcyclohexan-1-ones with Nbromosucccinimide and were isomerized into 6-bromo-2-aroylcyclohexan-1-ones in attempted dehydrobromination by heating in organic solvents. The reaction of 2-benzoyldimedone with oxalyl chloride was investigated. The 2-benzoyl-3-chloro-5,5-dimethyl-2-cyclohexen-1-one obtained formed 2-benzoyl-5,5-dimethyl-2-cyclohexen-1-one in reduction with zinc activated with silver acetate. The cyclohexenone was reacted with some enaminocarbonyl compounds, yielding derivatives of decahydrophenanthridine-1,7-dione and hexahydro-8-isoquinolone.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 631–635, May, 1992.     

Homologues of p-Menthane Derivatives in Roman Camomile

5-Isopropyl-2-propyl-2-cyclohexen-1-one ( 1 ) and 5-isopropyl-2-(2-methylpropyl)-2-cyclohexen-1-one ( 2 ), homologues of the p-methene ketone carvotanacetone, have been identified in the oil of Anthemis nobilis. Their synthesis involved allylation of a cyclohexane-1,3-dione, and the acid-catalyzed cyclization to dihydrofurans of the 2-allylcyclohexane-1,3-diones is described. The stereochemistry of metal hydride reduction of 3-ethoxy-5-isopropyl-2-propyl-2-cyclohexen-1-one ( 18 ) is mentioned in the course of the synthesis of the natural products. Some biogenetic considerations are discussed.     

An alternative approach to para-C-H arylation of phenol: palladium-catalyzed tandem γ-arylation/aromatization of 2-cyclohexen-1-one derivatives

An efficient approach to prepare para-aryl phenols has been developed by using a Pd-catalyzed tandem γ-arylation/aromatization of 2-cyclohexen-1-one derivatives with aryl bromides. This approach provides various p-aryl phenols from the phenol surrogates, 2-cyclohexen-1-one derivatives, in a single reaction step on the basis of C-H arylation.     

新型多氧取代环己烯酮的合成

以莽草酸为起始原料,经酯化、丙酮叉保护顺式邻二羟基、叔丁基二甲硅烷保护羟基、还原、羟基酯化、脱保护基、保护反式邻二羟基、烯丙醇氧化,脱保护基共9步反应,合成了新型(5R,6S)-3-苯甲酰氧基亚甲基-5,6-二羟基-2-环己烯-1-酮,总产率19.3％,其结构经1H NMR,IR和HR-MS表征.     

Oxidation of Cyclohexene Catalyzed by PAMAM—SA—M Dendrimers

Oxidation of cyclohexene under 1 atmospheric pressure of molecular oxygen at 70℃ in the absence of solvent catalyzed by PAMAM-SA-M(Where PAMAM=polyamidoamine;SA=salicyaldehyde;M=metal ions Fe^3 ,Co^2 ,Ni^2 ,Mn^2 ,Cu^2 ,Zn^2 ,respectively) dendrimers, afforded 2-cyclohexen-1-ol 1,2-cyclohexen-1-one 2,7-oxabicyclo [4,1,0] heptane 3 and 7-oxabicyl [4,1,0] heptan-2-one 4 as the major products. The factors that affect this reaction are also discussed.     

Reactions of phenylthiotrimethylsilylmethyllithium: Preparation of α-phenylthioketones and additions to 2-cyclohexen-1-one

Phenylthiotrimethylsilylmethyllithium(1) was reacted with a variety of electrophiles, including some containing two functional groups. α-Phenylthiolketones were obtained from the reaction with esters. The anion(1) underwent either 1,2- or 1,4-addition, depending on the conditions used, with 2-cyclohexen-1-one.     

Condensed isoquinolines. 37.* Heterocyclization using 3-(arylamino)- and 3-(hetarylamino)isoquinolin-1(2H)-ones

The reaction of 3-NHR-isoquinolin-1(2H)-ones (R = Ar) with aromatic aldehydes in the presence of Me3SiCl or in acetic acid leads to the formation of derivatives of dibenzo[b,f][1, 8]naphthyridin-5(6H)- one and benzo[f]isoquino[3,4-b][1, 8]naphthyridine-5,9(6H,7H)-dione. The reaction for R = Het in the presence of Me3SiCl gives derivatives of 5H-pyrido[1',2':1,2]pyrimido[4,5-c]isoquinolin-5-one, benzo[f]isoquinoline[3,4-b][1,8]naphthyridine-5,9[6H,7H]-dione, and derivatives of new heterocyclic systems, 5H-pyrazino[1',2':1,2]pyrimido[4,5-c]isoquinolin-5-one, 5H-[1,3]thiazolo[3',2':1,2]pyrimido- [4,5-c]isoquinolin-5-one, 5-H-benzo[f]pyrazolo[3,4-b][1,8]naphthyridin-5-one, and isoquino[3,4-b]- [1,5]naphthyridin-5(6H)-one. The effect of the structure of substituent R and nature of the substituent in the benzaldehydes on the structure of the reaction products was studied.     

4-Azaindane-1,3-dione derivatives

6,6-Dimethyl-2-methyl(or phenyl)-9-ethoxycarbonyl-5,6,7,8-tetrahydro-4-azabenz[f]indane-1, 3,8-triones were synthesized by reaction of 3-ethoxalyl-5-R-cyclopentaae-1,2,4-triones with 3-amino-5,5-dimethyl-2-cyclohexen-1-one. The products were alkylated, brominated, reduced, and hydrolyzed.     

Chiral phosphorus ligands for the asymmetric conjugate addition of organocopper reagents

The asymmetric conjugate addition of medium order alkyl cuprate reagents. R₅Cu₃Li₂, to 2-cyclohexen-1-one. 2-cyclopenten-1-one and 2-cyctohepten-1-one, with the help of phosphorus ligand B^*, is described. 3-Alkyl substituted cyclohexanones are obtained in essentially optically pure form. The same chiral ligand, associated with CuI, in catalylic amount (10%), allows the asymmetric conjugate addition of Et₂Zn to 2-cyclohexen-1-one.     

Polymer-supported bisBINOL ligands for the immobilization of multicomponent asymmetric catalysts

[reaction: see text] Polymer-supported bisBINOL ligands were successfully utilized for the immobilization of multicomponent asymmetric catalysts. The polymer-supported Al-Li-bis(binaphthoxide) (ALB) catalyst was more effective than the dendrimer-supported ALB in the Michael reaction of 2-cyclohexen-1-one with dibenzyl malonate affording the adduct in 91% yield with 96% ee. The polymer was also effective for the immobilization of a mu-oxodititanium complex that promoted carbonyl-ene reaction of ethyl glyoxalate with alpha-methyl styrene to provide the adduct with up to 98% ee.     

The enantioselective synthesis of (-)-lycoramine with the Birch-Cope sequence

The first enantioselective synthesis of (-)-lycoramine has been achieved in 14 steps and 5% overall yield from the biaryl derivative 1. The synthesis applies the previously developed Birch-Cope sequence to create the key arylic quaternary stereocenter of (-)-lycoramine with excellent enantioselective control. The product of the Birch-Cope sequence, a versatile 4,4-disubstituted-2-carboxamide-2-cyclohexen-1-one, was elaborated through an intramolecular conjugate addition of a phenol to create the dihydrofuran ring. Chemoselective elaboration of the allyl group into an amide followed by a modified Pictet-Spengler reaction generated the azepine ring.     

6,11-Dioxa-D-homoanalogs of steroids by reaction of 2-acetyl-2-cyclohexen-1-ones with 4-hydroxycoumarins

Unsubstituted 2-acetyl-2-cyclohexetz-1-one reacts with 4-hydroxycoumarin following the pattern of a Diels -Alder heterodiene condensation to form 12-methyl-6,11-dioxa-9-hydroxy-D-homo-1,3,5(10), 12-tetraene-7,17a-dione. In the case of 2-acetyl-5,5-dimethyl-2-cyclohexen-1-one, reaction with both 4-hydroxy- and 4,7-dihydroxycoumarin follows the pattern of a Michael addition with the formation of 3-(2-acetyl-5,5-dimethyl-3-oxocyclohexyl)-4-hydroxy-and 4,7-dihydroxy coumarin respectively. Dehydration of both types of adduct gives 6,11-dioxa-D-homoanalogs of steroids.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 345–348, March, 1994.