Structural effects in solvolytic reactions. 50. Steric retardation in the solvolysis of tertiary endo bicyclic derivatives. Evidence that the exo:endo rate/product ratios for typical reactions in rigid U-shaped bicyclics is a general steric phenomenon

Brown, Herbert C.; Jagt, David L. Vander; Rothberg, Irvin; Hammar, W. James; Kawakami, James H.

doi:10.1021/jo00212a036

Cited by 12 publications

(2 citation statements)

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“…Exposure of 22 to lithium aluminum hydride 29 then made available the primary carbinol 23 , which was transformed under basic conditions 30 into the p -methoxybenzyl derivative. Although we were now positioned to effect the hydroboration−oxidation of 24 , initial probe experiments involving use of the borane·THF complex 31a proved disappointing in terms of regiochemistry, stereochemistry, and efficiency 31b…”

Section: Resultsmentioning

confidence: 99%

Total Synthesis of Spinosyn A. 1. Enantioselective Construction of a Key Tricyclic Intermediate by a Multiple Configurational Inversion Scheme

Paquette

Gao

et al. 1998

J. Am. Chem. Soc.

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The condensation of (+)-7,7-dimethoxynorbornen-2-one with the cerium reagent derived from enantiopure bromide (+)-11 gives rise to an exo carbinol, which readily undergoes highly stereocontrolled anionic oxy-Cope rearrangement. Conversion of the resulting ketone into 20 proceeds with clean epimerization at C-11 (spinosyn numbering) to properly set the absolute configuration at that site. Reduction of 20 with lithium in liquid ammonia serves to introduce two additional stereogenic centers of the perhydro-as-indacene core. In addition, the protocol makes possible the convenient incorporation of a functionalized two-carbon appendage at C-3 and ultimate generation of a cyclohexene double bond after stereochemical inversion at C-7. This scheme leads to 34, a tricyclic compound subsequently shown to be an advanced precursor to the powerful insecticide spinosyn A.

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Section: Resultsmentioning

confidence: 99%

Total Synthesis of Spinosyn A. 1. Enantioselective Construction of a Key Tricyclic Intermediate by a Multiple Configurational Inversion Scheme

Paquette

Gao

et al. 1998

J. Am. Chem. Soc.

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“…Diels-Alder (DA) cycloaddition reactions are a powerful tool in organic synthesis and in the chemical industries, and therefore the DA reaction has been extensively studied by both experimental and theoretical methods [5][6][7]. Solvents have many effects on this type of reaction such as kinetic and product selectivity which are investigated using theoretical methods [8][9][10][11][12]. In this article, solvent effects on the DA reaction of cyclopentadiene (R1) and methyl acrylate (R2) have been investigated using the combined methods of quantum mechanics and molecular mechanics (QM/MM).…”

Section: Introductionmentioning

confidence: 99%

Implicit and explicit solvent effects on the selectivity of the cycloaddition reaction of cyclopentadiene and methyl acrylate; a theoretical study

Khavani

Izadyar

2015

Progress in Reaction Kinetics and Mechanism

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The product selectivity of the Diels-Alder reaction between cyclopentadiene and methyl acrylate has been studied through a solvent effect analysis by implicit and explicit solvent models. Two paths for this reaction have been proposed and thermodynamic and kinetic parameters for each path were calculated by the B3LYP functional with 6-311++G(d,p) basis set at 298.15 K. In the explicit solvent model, hydrogen bonds were investigated by the QM/MM method. According to the results, the proportion of the exo product in the gas phase is more than for the endo one, which is in contrast to the solvent phase. HOMO-LUMO analyses in the gas phase and different solvents have been done and solvent effects on the energies of the HOMO-LUMO orbitals were investigated. According to the results, the band gap of the TSs was increased in the presence of the solvents. Finally, natural population analysis has been performed to calculate the electronic charges of some atoms that are involved in the centre of the reaction. The data obtained showed that different solvents, including polar and nonpolar solvents, have different effects on the electronic charges of the atoms. Topological analysis of the structures during the reaction by the quantum theory of atoms in molecules (QTAIM) method in the gas phase and different solvents confirmed a cyclic structure for the transition state.

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Formation of Alkenes by Elimination

Larock

Zeni

2018

Comprehensive Organic Transformations

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Dehydrogenation Dehydrohalogenation and Elimination of Alkyl Halides 1,1‐Dihalides 1,2‐Dihalides 1,3‐Dihalides Trihaloalkanes β‐Halo Ethers Halohydrins Halo Aldehydes and Ketones Halo Carboxylic Acids Halo Esters β‐Halo Sulfonates Amines β‐Halo Amines and Derivatives Amine Oxides (Cope Elimination) Quaternary Ammonium Salts N ‐Alkyl‐ N , N ‐Disulfonimides N ‐Nitrosocarboxamides Nitro Compounds Diazo Compounds β‐Substituted Azides Ethers β‐Substituted Ethers Sulfides α‐Halosulfides β‐Halosulfides β‐Hydroxysulfides Sulfoxides β‐Alkoxy‐ and Hydroxy‐Sulfoxides Sulfones α‐Halosulfones (Ramberg—Bäcklund Reaction) β‐Hydroxysulfones β‐Acyloxysulfones Other β‐Substituted Sulfones Disulfones Sulfonyl Halides β‐Oxyselenides Selenoxides Tellurides Organosilanes β‐Halosilanes β‐Oxysilanes and ‐Stannanes β‐Aminosilanes Dehydration of Alcohols Sulfonate Esters Sulfates Phosphates and Thiophosphates Xanthates Thiocarbonates Carbamates N ‐Methyl‐4‐alkoxypyridinium Iodides 1,2‐Diols and Derivatives 1,2‐Disulfonates 1,3‐Diols Acetals Dithioacetals Aldehydes and Ketones Lactols Carboxylic Acids Acid Halides Acid Anhydrides Esters and Lactones Amides and Lactams Nitriles Miscellaneous Reactions

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Structural effects in solvolytic reactions. 50. Steric retardation in the solvolysis of tertiary endo bicyclic derivatives. Evidence that the exo:endo rate/product ratios for typical reactions in rigid U-shaped bicyclics is a general steric phenomenon

Cited by 12 publications

References 0 publications

Total Synthesis of Spinosyn A. 1. Enantioselective Construction of a Key Tricyclic Intermediate by a Multiple Configurational Inversion Scheme

Total Synthesis of Spinosyn A. 1. Enantioselective Construction of a Key Tricyclic Intermediate by a Multiple Configurational Inversion Scheme

Implicit and explicit solvent effects on the selectivity of the cycloaddition reaction of cyclopentadiene and methyl acrylate; a theoretical study

Formation of Alkenes by Elimination

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