Browse
Submit Data
Databases
API
Help

Dataset Information

28 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

A bidirectional S(E)' strategy for 1,5-syn and 1,5-anti stereocontrol toward the synthesis of complex polyols.

ABSTRACT: Studies report a bidirectional S(E)' strategy applicable for the stereocontrolled synthesis of nonracemic 1,5-syn and 1,5-anti diols and their derivatives. Nonracemic 1,3,2-diazaborolidine auxiliaries are incorporated by chemoselective tin-boron exchange to provide reactive allylic boranes. The convergent pathway utilizes sequential reactions with two aldehydes producing stereochemical outcomes from cyclic, closed, and open transition state preferences, respectively. Synthesis of fragment 16 of peloruside A is accomplished in four steps from readily available aldehydes 9 and 13.

SUBMITTER: Williams DR

PROVIDER: S-EPMC3565749 | biostudies-literature | 2012 Aug

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

A bidirectional S(E)' strategy for 1,5-syn and 1,5-anti stereocontrol toward the synthesis of complex polyols.

Williams David R DR Claeboe Christopher D CD Liang Bo B Zorn Nicolas N Chow Nicholas S C NS

Organic letters 20120719 15

Studies report a bidirectional S(E)' strategy applicable for the stereocontrolled synthesis of nonracemic 1,5-syn and 1,5-anti diols and their derivatives. Nonracemic 1,3,2-diazaborolidine auxiliaries are incorporated by chemoselective tin-boron exchange to provide reactive allylic boranes. The convergent pathway utilizes sequential reactions with two aldehydes producing stereochemical outcomes from cyclic, closed, and open transition state preferences, respectively. Synthesis of fragment 16 of ...[more]

PMID: 22813207

Similar Datasets

Stereoselective synthesis of syn,syn- and syn,anti-1,3,5-triols via intramolecular hydrosilylation of substituted pent-3-en-1,5-diols.

Project description:A stereoselective method for synthesis of syn,syn- and syn,anti-1,3,5-triols based on a double allylboration-intramolecular hydrosilylation sequence has been developed. The 1,3-syn stereocontrol is achieved in the intramolecular hydrosilylation of monoprotected (Z)-1,5-syn-diols and (E)-1,5-anti-diols with 87:13 to 95:5 and 86:14 to 88:12 diastereomeric ratios, respectively, by using 0.5 mol % of Karstedt's catalyst in toluene.

| S-EPMC2755244 | biostudies-literature

Synthesis of 2,6-trans-disubstituted 5,6-dihydropyrans from (Z)-1,5-syn-endiols.

Project description:Certain (Z)-1,5-syn-diols 2 may be converted into 2,6-trans-5,6-dihydropyrans by using phosphonium salt 4 or phosphorane 5 as dehydrating agents. A more general four step procedure converts the (Z)-1,5-syn-endiols into enantiomeric dihydropyrans ent-3 via regioselective silylation of the allylic alcohol unit followed by mesylate formation and base-promoted nucleophilic displacement.

| S-EPMC1399455 | biostudies-literature

A modular phosphate tether-mediated divergent strategy to complex polyols.

Project description:An efficient and divergent synthesis of polyol subunits utilizing a phosphate tether-mediated, one-pot, sequential RCM/CM/reduction process is reported. A modular, 3-component coupling strategy has been developed, in which, simple "order of addition" of a pair of olefinic-alcohol components to a pseudo-C 2-symmetric phosphoryl chloride, coupled with the RCM/CM/reduction protocol, yields five polyol fragments. Each of the product polyols bears a central 1,3-anti-diol subunit with differential olefinic geometries at the periphery.

| S-EPMC4187035 | biostudies-literature

Concerning the selective protection of (Z)-1,5-syn-ene-diols and (E)-1,5-anti-ene-diols as allylic triethylsilyl ethers.

Project description:Treatment of unsaturated 1,5-diols 2 with TES-Cl (1.1 equiv), imidazole, and catalytic DMAP in 1:1 CH2Cl2-DMF at -78 degrees C effects selective silylation of the allylic alcohol with >95:5 chemoselectivity when the allylic and homoallylic alcohols are in similar steric environments.

| S-EPMC2504016 | biostudies-literature

Intermolecular radical addition to N-acylhydrazones as a stereocontrol strategy for alkaloid synthesis: formal synthesis of quinine.

Project description:Stereocontrolled Mn-mediated radical addition of alkyl iodides to chiral N-acylhydrazones enables strategic C-C bond disconnection of chiral amines. This strategy was examined in the context of a total synthesis of quinine, generating new findings of functional group compatibility leading to a revised strategy. Completion of a formal synthesis of quinine is presented, validating the application of Mn-mediated radical addition as a useful new C-C bond construction method for alkaloid synthesis. The Mn-mediated addition generates the chiral amine substructure of quinine with complete stereocontrol. Subsequent elaboration includes two successive ring closures to forge the azabicyclo[2.2.2]octane ring system of quincorine, linked to quinine through two known reactions.

| S-EPMC4114234 | biostudies-literature

Enantio- and diastereoselective synthesis of (E)-1,5-syn-diols: application to the synthesis of the C(23)-C(40) fragment of tetrafibricin.

Project description:A highly stereoselective synthesis of (E)-1,5-syn-diols 6 is described. The kinetically controlled hydroboration of allenyltrifluoroborate 8 with Soderquist borane 2 provides the (Z)-allylic trifluoroborate 9, which undergoes sequential allylboration with two different aldehydes to provide (E)-1,5-syn-diols 6 in 72-98% yields with >95% ee and >20:1 dr. Application of this method to the synthesis of the tetrafibricin C(23)-C(40) fragment 19 is described.

| S-EPMC3064748 | biostudies-literature

De novo synthesis of 2-substituted syn-1,3-diols via an iterative asymmetric hydration strategy.

Project description:The enantioselective syntheses of several protected 4-substituted syn-3,5-dihydroxy carboxylic esters have been achieved from the corresponding achiral (E,E)- or (E,Z)-1,3-dienoates. The route relies upon an enantio- and regioselective Sharpless dihydroxylation and a palladium-catalyzed reduction to form gamma-substituted delta-hydroxy-1-enoates. The resulting delta-hydroxy-1-enoates are subsequently converted into benzylidene-protected 4-substituted syn-3,5-dihydroxy carboxylic esters in one step. The benzylidene-protected 3,5-dihydroxy carboxylic esters are produced in good overall yields (20-54%) and high enantiomeric excess (73-97% ee).

| S-EPMC2515821 | biostudies-literature

One-pot synthesis of enantiopure syn-1,3-diacetates from racemic syn/anti mixtures of 1,3-diols by dynamic kinetic asymmetric transformation.

Project description:A one-pot synthesis of enantiomerically pure syn-1,3-diacetates starting from readily accessible racemic diastereomeric mixtures of 1,3-diols has been realized by combining (i) enzymatic transesterification, (ii) ruthenium-catalyzed epimerization of a secondary alcohol in a diol or diol monoacetate, and (iii) intramolecular acyl migration in a syn-1,3-diol monoacetate. The in situ coupling of these three processes results in an efficient enantioselective synthesis of acyclic syn-1,3-diacetates via combined deracemization-deepimerization and constitutes a dynamic kinetic asymmetric transformation concept. Several differently substituted unsymmetrical, acyclic syn-1,3-diacetates were obtained in yields up to 73% with excellent enantioselectivities (>99%) and good diastereomeric ratios (>90% syn).

| S-EPMC395981 | biostudies-literature

Evolution of a Unified Strategy for Complex Sesterterpenoids: Progress toward Astellatol and the Total Synthesis of (-)-Nitidasin.

Project description:Astellatol and nitidasin belong to a subset of sesterterpenoids that share a sterically encumbered trans-hydrindane motif with an isopropyl substituent. In addition, these natural products feature intriguing polycyclic ring systems, posing significant challenges for chemical synthesis. Herein, the evolution of our stereoselective strategy for isopropyl trans-hydrindane sesterterpenoids is detailed. These endeavors included the synthesis of several building blocks, enabling studies toward all molecules of this terpenoid subclass, and of advanced intermediates of our initial route toward a biomimetic synthesis of astellatol. These findings provided the basis for a second-generation and a third-generation approach toward astellatol that eventually culminated in the enantioselective total synthesis of (-)-nitidasin. In particular, a series of substrate-controlled transformations to install the ten stereogenic centers of the target molecule was orchestrated and the carbocyclic backbone was forged in a convergent fashion. Furthermore, the progress toward the synthesis of astellatol is disclosed and insights into some observed yet unexpected diastereoselectivities by detailed quantum-mechanical calculations are provided.

| S-EPMC4696511 | biostudies-literature

A strategy toward the synthesis of C13-oxidized cembrenolides.

Project description:An efficient strategy for the construction of C13-oxidized cembrenolides is reported. Central to this strategy is the installation of the C13 hydroxyl group prior to cembrane macrocyclization (via formation of the C1-C2 bond), allowing access to both C13 alcohol epimers. The orientation of the C13 alcohol was found to influence the cyclization mode of the cembranolide scaffold upon furan oxidation, leading to motifs reminiscent to bipinnatolide F, bielschowskysin, and verrillin.

| S-EPMC3634613 | 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