Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Origin of thermodynamic versus kinetic control of allene hydroboration with 9-borabicyclo[3.3.1]nonane and 10(R)-trimethylsilyl-9-borabicyclo[3.3.2]decane.

ABSTRACT: Density functional theory was used to locate transition states for hydroboration reactions of allenes with 9-borabicyclo[3.3.1]nonane and 10-R-9-borabicyclo[3.3.2]decane, as well as transition states for [1,3]-boratropic shift and aldehyde addition reactions of the derived allylboranes. The origin of kinetic versus thermodynamic control in the allene hydroboration step is described.

SUBMITTER: Ess DH

PROVIDER: S-EPMC2803353 | biostudies-literature | 2009 Dec

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Origin of thermodynamic versus kinetic control of allene hydroboration with 9-borabicyclo[3.3.1]nonane and 10(R)-trimethylsilyl-9-borabicyclo[3.3.2]decane.

Ess Daniel H DH Kister Jeremy J Chen Ming M Roush William R WR

Organic letters 20091201 23

Density functional theory was used to locate transition states for hydroboration reactions of allenes with 9-borabicyclo[3.3.1]nonane and 10-R-9-borabicyclo[3.3.2]decane, as well as transition states for [1,3]-boratropic shift and aldehyde addition reactions of the derived allylboranes. The origin of kinetic versus thermodynamic control in the allene hydroboration step is described. ...[more]

PMID: 19899749

Similar Datasets

Quantum-mechanical study of 10-R-9-borabicyclo[3.3.2]decane alkene hydroboration.

Project description:Density functional theory and correlated ab initio quantum mechanical methods were used to locate and analyze alkene hydroboration transition structures for 10-R-9-borabicyclo[3.3.2]decane reagents. Transition-state ensembles quantitatively modeled enantioselectivity for hydroboration of cis-, trans-, and gem-disubstituted alkenes in excellent agreement with experiment. The 10-R group and borabicyclo[3.3.2]decane ring conformation effects were analyzed to understand the origin of asymmetric selectivity.

| S-EPMC2803351 | biostudies-literature

Stereoselective synthesis of gamma-substituted (Z)-allylic boranes via kinetically controlled hydroboration of allenes with 10-TMS-9-borabicyclo[3.3.2]decane.

Project description:Kinetically controlled hydroboration of allenes 8 and 14a-d with the readily accessible Soderquist borane 7, which is generated in situ from borohydride 6, constitutes a convenient and preparatively useful method for synthesis of (Z)-gamma-(substituted)allylboranes 9 and 15a-d. These allylboranes undergo highly diastereo- (> or = 90: 10) and enantioselective (typically 89-96% e.e.) allylboration reactions with representative aldehydes to give syn-beta-functionalized homoallylic alcohols.

| S-EPMC2767336 | biostudies-other

Enantio- and diastereoselective synthesis of syn-β-hydroxy-α-vinyl carboxylic esters via reductive aldol reactions of ethyl allenecarboxylate with 10-TMS-9-Borabicyclo[3.3.2]decane and DFT analysis of the hydroboration pathway.

Project description:An enantio- and diastereoselective synthesis of syn-β-hydroxy-α-vinyl carboxylate esters 3 via the reductive aldol reaction of ethyl allenecarboxylate (2) with 10-trimethylsilyl-9-borabicyclo[3.3.2]decane (1R) has been developed. Density functional theory calculations suggest that the allene hydroboration involves the 1,4-reduction of 2 with the 1R, leading directly to dienolborinate Z-(O)-8a.

| S-EPMC3849616 | biostudies-literature

Nonracemic 3 degrees-carbamines from the asymmetric allylboration of N-trimethylsilyl ketimines with B-allyl-10-phenyl-9-borabicyclo[3.3.2]decanes.

Project description:The simple and efficient asymmetric synthesis of 3 degrees -carbamines 7 from N-TMS enamines (3) and either enantiomeric form of beta-allyl-10-(phenyl)-9-borabicyclo[3.3.2]decane (1) is reported. The high reactivity (<1 h, -78 degrees C) and enantioselectivity (60-98% ee) of these substrates can be attributed to the fact that the complexation of 3 with 1 facilitates its isomerization to the corresponding syn-N-TMS ketimine complex from which allylation can occur. In addition to providing the homoallylic amines 7 with predictable stereochemistry, the procedure also permits the efficient recovery of the chiral boron moiety (50-65%) as air-stable crystalline pseudoephedrine complexes 8, which are directly converted back to 1 with allylmagnesium bromide in ether (98%).

| S-EPMC2572578 | biostudies-other

2-Isobutyl-2-phosphabicyclo-[3.3.1]nonane 2-selenide.

Project description:The title compound, C(12)H(23)PSe, represents the first structure of a phosphine containing the bicyclic 2-phospha-bicyclo-[3.3.1]nonane (VCH) unit. It contains two chiral centres per mol-ecule which can be either R,R- or S,S and crystallizes as a centrosymmetric, racemic micture of the enanti-omers. The P-Se bond distance of 2.1360?(16)?Å is typical for these compounds. The Tolman cone angle (2.28?Å from P) was calculated as 163°, and the effective cone angle (using the crystallographically determined P-Se bond distance) is 168°.

| S-EPMC2968513 | biostudies-literature

rac-4,8-Divinyl-bicyclo-[3.3.1]nonane-2,6-dione.

Project description:The title compound, C(13)H(16)O(2), is a chiral bicyclic structure composed of two fused cyclo-hexa-ne rings possessing both boat and chair conformations. The mol-ecules are packed in enantio-pure columns which are pairwise linked forming an overall racemic solid; within the column pairs the packing is governed by weak dipole-dipole inter-actions stemming from stacked carbonyl functionalities (CO(centroid)-CO(centroid) distance = 3.290 Å).

| S-EPMC2969760 | biostudies-literature

Crystal structures and supra-molecular features of 9,9-dimethyl-3,7-di-aza-bicyclo-[3.3.1]nonane-2,4,6,8-tetra-one, 3,7-di-aza-spiro-[bi-cyclo-[3.3.1]nonane-9,1'-cyclo-penta-ne]-2,4,6,8-tetra-one and 9-methyl-9-phenyl-3,7-di-aza-bicyclo-[3.3.1]nonane-2,4,6,8-tetra-one di-methyl-formamide monosolvate.

Project description:Compounds (I), C9H10N2O4, (II), C11H12N2O4, and (III), C14H12N2O4·C3H7NO represent 9,9-disubstituted-3,7-di-aza-bicyclo-[3.3.1]nonane-2,4,6,8-tetra-one deriv-atives with very similar mol-ecular geometries for the bicyclic framework: the dihedral angle between the planes of the imide groups is 74.87 (6), 73.86 (3) and 74.83 (6)° in (I)-(III), respectively. The dimethyl derivative (I) is positioned on a crystallographic twofold axis and its overall geometry deviates only slightly from idealized C2v symmetry. The spiro-cyclo-pentane derivative (II) and the phen-yl/methyl analog (III) retain only inter-nal Cs symmetry, which in the case of (II) coincides with crystallographic mirror symmetry. The cyclo-pentane moiety in (II) adopts an envelope conformation, with the spiro C atom deviating from the mean plane of the rest of the ring by 0.548 (2) Å. In compound (III), an N-H⋯O hydrogen bond is formed with the di-methyl-formamide solvent mol-ecule. In the crystal, both (I) and (II) form similar zigzag hydrogen-bonded ribbons through double inter-molecular N-H⋯O hydrogen bonds. However, whereas in (I) the ribbons are formed by two trans-arranged O=C-N-H amide fragments, the amide fragments are cis-positioned in (II). The formation of ribbons in (III) is apparently disrupted by participation of one of its N-H groups in hydrogen bonding with the solvent mol-ecule. As a result, the mol-ecules of (III) form zigzag chains rather than the ribbons through inter-molecular N-H⋯O hydrogen bonds. The crystal of (I) was a pseudo-merohedral twin.

| S-EPMC5499299 | biostudies-literature

Asymmetric synthesis of 2 degrees- and 3 degrees-Carbinols via B-methallyl-10-(TMS and Ph)-9-borabicyclo[3.3.2]decanes.

Project description:Simple Grignard procedures provide methallylboranes 1a and 1b in enantiomerically pure form from air-stable precursors in 98% and 95% yields, respectively. These reagents add smoothly to aldehydes and methyl ketones, respectively, providing branched 2 degrees- (6, 69-89%, 94-99% ee) and 3 degrees- (10, 71-87%, 74-96% ee) homoallylic alcohols.

| S-EPMC2563422 | biostudies-literature

(1R*,2R*,4S*,5R*,6R*,8S*)-4,8-Dimethyl-2,6-diphenyl-bicyclo-[3.3.1]nonane-2,6-diol.

Project description:The racemic title compound, C(23)H(28)O(2), crystallizes in the space group C2/c as a layered structure in which a centrosymmetric three hydrogen bond sequence links four molecules. Both hydroxy groups are involved in this arrangement, but they differ in that one participates in two hydrogen bonds while the other takes part in only one. Between layers, the aromatic rings take part in edge-face interactions [shortest C-H⋯C distances 3.04, 3.10 and 3.12 Å and angle between normal to planes 86.7(2)°], forming a centrosymmetric dimer. The lattice is further stabilized by C-H⋯π interactions involving both methyl (shortest C⋯C 3.82 and 3.97 Å) and methylene (shortest C⋯C 3.60 Å) groups.

| S-EPMC2968924 | biostudies-literature

Synthesis and hLDH Inhibitory Activity of Analogues to Natural Products with 2,8-Dioxabicyclo[3.3.1]nonane Scaffold

Project description:Human lactate dehydrogenase (hLDH) is a tetrameric enzyme present in almost all tissues. Among its five different isoforms, hLDHA and hLDHB are the predominant ones. In the last few years, hLDHA has emerged as a therapeutic target for the treatment of several kinds of disorders, including cancer and primary hyperoxaluria. hLDHA inhibition has been clinically validated as a safe therapeutic method and clinical trials using biotechnological approaches are currently being evaluated. Despite the well-known advantages of pharmacological treatments based on small-molecule drugs, few compounds are currently in preclinical stage. We have recently reported the detection of some 2,8-dioxabicyclo[3.3.1]nonane core derivatives as new hLDHA inhibitors. Here, we extended our work synthesizing a large number of derivatives (42–70) by reaction between flavylium salts (27–35) and several nucleophiles (36–41). Nine 2,8-dioxabicyclo[3.3.1]nonane derivatives showed IC50 values lower than 10 µM against hLDHA and better activity than our previously reported compound 2. In order to know the selectivity of the synthesized compounds against hLDHA, their hLDHB inhibitory activities were also measured. In particular, compounds 58, 62a, 65b, and 68a have shown the lowest IC50 values against hLDHA (3.6–12.0 µM) and the highest selectivity rate (>25). Structure–activity relationships have been deduced. Kinetic studies using a Lineweaver–Burk double-reciprocal plot have indicated that both enantiomers of 68a and 68b behave as noncompetitive inhibitors on hLDHA enzyme.

| S-EPMC10298284 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data