A stereo-divergent route to aminocyclopentitol derivatives (original) (raw)

Stereospecific synthesis of a new class of aminocyclitol with the conduramine D-2 configuration

Tetrahedron Letters, 2006

A new aminocyclitol derived from bicyclo[4.2.0 1,6 ]octane was synthesized starting from cyclooctatetraene. Photooxygenation of trans-7,8-diacetoxy-bicyclo[4.2.0]octa-2,4-diene afforded a bicyclic endoperoxide. Reduction of the endoperoxide with thiourea followed by a palladium-catalyzed ionization/cyclization reaction gave an oxazolidinone derivative. Oxidation of the double bond in the oxazolidinone with KMnO 4 followed by acetylation gave the oxazolidinone-tetraacetate whose exact configuration was determined by X-ray diffraction analysis. Hydrolysis of the oxazolidinone ring and removal of the acetate groups furnished the desired aminocyclitol.

Highly efficient chemoenzymatic syntheses of trans-2-aminocyclopentanol derivatives

Journal of Molecular Catalysis B: Enzymatic, 2009

A novel and efficient chemoenzymatic protocol for the preparation of both enantiomers of trans-2-aminocyclopentanol is described. The key steps of this strategy are the synthesis and subsequent Burkholderia cepacia lipase-catalyzed resolution of the racemic precursor trans-2-(diallylamino)cyclopentanol. In addition, a variety of diversely substituted derivatives are prepared from the enantiopure compounds isolated in the biotransformation by means of simple protection-deprotection reactions.

Synthesis of five and six membered aminocyclitols: stereoselective Michael and Henry reaction approach with d-glucose derived α,β-unsaturated ester

Tetrahedron, 2008

The stereoselective intermolecular Michael addition of nitromethane to D-glucose derived a,b-unsaturated ester 7 afforded L-ido-configurated nitroester 8 as the only product that on reduction of the ester functionality, cleavage of 1,2-acetonide and the intramolecular Henry reaction afforded exclusively muco-nitroinositol 9. While reduction of the ester functionality in 8, deprotection of 1,2-acetonide, oxidative cleavage with NaIO 4 and the intramolecular Henry reaction afforded nitrocyclopentitol 13. Nitrocyclitols 9 and 13 were converted to the hydroxyethyl substituted aminocyclohexitol 5 and aminocyclopentitol 6, respectively.

An Auxiliary‐Mediated Alkylation Approach Towards the Synthesis of β‐Amino Carbonyl Derivatives

ChemistrySelect, 2017

Asymmetric Mannich‐type reaction employing 5‐isopropyl‐3‐phenyl‐2‐thioxoimidazolidin‐4‐one as a chiral auxiliary with various aldimines to obtain enantiomerically enriched β‐amino carbonyl functionalities with good yields and high trans‐diastereoselectivities has been described. In order to establish the stereochemical outcome of the reaction, the Mannich‐adduct was hydrolysed using LiOH/H2O2 and subsequently cyclized with thionyl chloride to afford the corresponding β‐lactam in good yield and high stereoselectivity.

Synthesis of Aminocyclitols by Intramolecular Reductive Coupling of Carbohydrate Derived δ- and ε-Functionalized Oxime Ethers Promoted by Tributyltin Hydride or Samarium Diiodide

Journal of Organic Chemistry, 1997

The intramolecular reductive coupling of a series of simple or polyoxygenated oxime ethers δ-or -functionalized with bromide, R, -unsaturated ester, aldehyde, or ketone groups is reported. The cyclization of a nitrile-tethered aldehyde is also studied. These reductive couplings are promoted by tributyltin hydride or samarium diiodide. The reactions proceed under mild conditions, in good chemical yield, and with high stereoselectivity. When applied to highly functionalized substrates derived from carbohydrates, this approach provides a selective entry to enantiomerically pure aminocyclitols of varying regio-and stereochemistry. In particular, the reductive coupling reaction of carbonyl-tethered oxime ethers promoted by samarium diiodide can be performed in a one-pot sequence, following a Swern oxidation step, allowing the direct transformation of hydroxyl-tethered oxime ethers into the corresponding aminocyclitols. Moreover, the resultant O-benzylhydroxylamine products of these cyclizations can be further reduced in situ with excess samarium diiodide, in the presence of water, to the corresponding amino alcohols in excellent yields. Some transformations of these compounds are discussed. Kimura, H.; Uchida, C.; Ohashi, T. J. Chem. Soc., Perkin Trans. 1 1995, 1695, and references cited therein.

Carbocyclic α-amino acids: asymmetric Strecker synthesis of a series of 2-alkylated 1-aminocyclopentanecarboxylic acids

Tetrahedron: Asymmetry, 2000

A series of 12 carbocyclic a-amino acids has been prepared from four dierent racemic 2-alkylated cyclopentanones and (R)-1-phenylethylamine as the chiral auxiliary by means of an asymmetric Strecker synthesis. The stereoselectivity was in¯uenced by solvent, temperature and size of the substituent at the 2-position of the cyclopentanones. For the methyl and ethyl substituted amino acids all four possible stereoisomers could be obtained, whereas for the isopropyl and tertiary butyl compounds an unexpected side reaction prohibited the isolation of the cis con®gured amino acids. The 1,3-induction mechanism observed for the kinetically controlled a-amino nitrile formation in the 2-methyl and 2-ethyl series was overlayed by a 1,2-induction in the respective 2-isopropyl and 2-tertiary butyl series. #