Total Synthesis of Monosaccharides. Synthesis of Methyl DL-Pentopyranosides with α- and β-lyxo, β-ribo, α-xylo, and α-arabino Configurations from Furfuryl Alcohol

1975 ◽  
Vol 53 (17) ◽  
pp. 2524-2529 ◽  
Author(s):  
Osman Achmatowicz Jr. ◽  
Pawel Bukowski
Keyword(s):  
Total Synthesis ◽  
Ring Opening ◽  
Furfuryl Alcohol ◽  
Oxirane Ring

Hydroxylation and epoxidation, followed by the oxirane ring opening, of methyl 2,3-dideoxy-α and β-DL-pent-2-enopyranosides, readily available by the transformation of furfuryl alcohol, afforded the title compounds. Steric course of hydroxylation and epoxidation reactions were examined. The p.m.r. data of methyl 4-O-acetyl-2,3-anhydro-DL-pentopyranosides are reported.

Acid-Catalyzed Ring-Opening Cyclization of Spirocyclopropanes for the Construction of a 2-Arylbenzofuran Skeleton: Total Synthesis of Cuspidan B

Synthesis ◽  
2016 ◽  
Vol 48 (12) ◽  
pp. 1892-1901 ◽  
Author(s):  
Hisanori Nambu ◽  
Takayuki Yakura ◽  
Naoki Ono
Keyword(s):  
Total Synthesis ◽  
Ring Opening ◽  
Acid Catalyzed

An analysis of the factors contributing to the regioselectivity observed in the opening of oxiranes

1980 ◽  
Vol 58 (3) ◽  
pp. 302-306 ◽  
Author(s):  
Margaret M. Kayser ◽  
Peter Morand
Keyword(s):  
Oxygen Atom ◽  
Ring Opening ◽  
Oxirane Ring ◽  
Epoxide Ring ◽  
Acid Base ◽  
Epoxide Ring Opening ◽  
Soft Acid ◽  
Hsab Theory

The regioselectivity of epoxide ring opening can be analyzed in terms of hard–soft acid–base (HSAB) theory. The coordination of the hard acid with the oxygen atom of the oxirane ring produces a "pulling effect" which determines the direction of the ring opening. In the absence of a strong "pulling effect" the "pushing effect" of the approaching base is examined and the consequences of relative softness or hardness of the nucleophile on the regioselectivity of the ring opening are discussed.

First Total Synthesis of a Fluorinated Calystegin

2010 ◽  
Vol 65 (4) ◽  
pp. 445-451 ◽  
Author(s):  
René Csuk ◽  
Erik Prell ◽  
Stefan Reißmann ◽  
Claudia Korb
Keyword(s):  
Total Synthesis ◽  
Ring Opening ◽  
Competitive Inhibitor ◽  
Ring Closure ◽  
Target Compound ◽  
Metathesis Reaction ◽  
Grubbs Catalyst ◽  
Ring Opening Reaction ◽  
Ultrasound Assisted ◽  
Key Steps

A straightforward chiral pool synthesis for the first fluorinated calystegin is described. Key steps of this synthesis include an ultrasound-assisted Zn-mediated tandem ring opening reaction followed by a Grubbs’ catalyst-mediated ring closure metathesis reaction. The target compound is a selective and competitive inhibitor for a β -glycosidase.

Are amines basic or nucleophilic catalysts for oxirane ring opening by proton-donating nucleophiles?

2016 ◽  
Vol 57 (1) ◽  
pp. 47-51 ◽  
Author(s):  
S. G. Bakhtin ◽  
E. N. Shved ◽  
Yu. N. Bespal’ko
Keyword(s):  
Ring Opening ◽  
Oxirane Ring ◽  
Nucleophilic Catalysts

Total Synthesis of Resolvin T4

Synlett ◽  
2021 ◽  
Author(s):  
Narihito Ogawa ◽  
Kohei Arai ◽  
Yuichi Kobayashi
Keyword(s):  
Total Synthesis ◽  
Ring Opening ◽  
Transfer Hydrogenation ◽  
Asymmetric Transfer Hydrogenation ◽  
Ring Opening Reaction ◽  
Propargylic Alcohol ◽  
Chiral Centers ◽  
Wittig Reactions

AbstractA total synthesis of resolvin T4 was achieved by connecting three intermediates by Wittig reactions. The enal in the C1–C10 part was constructed through reduction of a propargylic alcohol with Red-Al followed by oxidation. The enal moiety in the C11–C16 part was synthesized by a ring-opening reaction of a silyl epoxide followed by a Peterson elimination. The chiral centers at C7 and C13 were constructed by ruthenium-catalyzed asymmetric transfer hydrogenation.

Structural Investigation of a Configurationally Stable Seven-Membered Bridged Biaryl of Relevance for Atroposelective Biaryl Syntheses*

2003 ◽  
Vol 58 (2-3) ◽  
pp. 231-236 ◽  
Author(s):  
Gerhard Bringmann ◽  
Robert-Michael Pfeifer ◽  
Christian Rummey ◽  
Thomas Pabst ◽  
Dirk Leusser ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Ring Opening ◽  
Structural Investigation ◽  
X Ray Diffraction ◽  
Cleavage Reaction ◽  
Perfect Agreement ◽  
X Ray ◽  
Ether Bridge ◽  
Axially Chiral ◽  
Aromatic Systems

The atroposelective ring opening of lactone-bridged biaryl systems is the key step in the total synthesis of a series of axially chiral biaryl natural products and useful reagents or catalysts for asymmetric synthesis. For a more in-depth understanding of the mechanism and stereochemical course of this remarkable cleavage reaction, a seven-membered ether analog of such useful biaryl lactones has been investigated structurally, both experimentally, by X-ray diffraction analysis, and by ab initio calculations (B3LYP/6-31G*). In a nearly perfect agreement, both methods show that these seven-membered bridged biaryls do not constitute helicene-like distorted molecules, but ‘true’ biaryls, whose sufficiently long lactone or ether bridge allows the two aromatic systems to adopt a large dihedral angle to each other, without any noticeable deviation from planarity for the two aromatic systems - in contrast to related six-membered analogs, which can rather be considered as helicene-like twisted polycyclic systems.

ChemInform Abstract: Oxirane Ring-Opening with Alcohol Catalyzed by Organotin Phosphate Condensates. Complete Inversion at Tertiary and Benzylic Centers.

ChemInform ◽  
2010 ◽  
Vol 23 (2) ◽  
pp. no-no
Author(s):  
J. OTERA ◽  
Y. NIIBO ◽  
H. NOZAKI
Keyword(s):  
Ring Opening ◽  
Oxirane Ring ◽  
Complete Inversion

scholarly journals Behaviour Modelling of Organic Bases in the Oxyalkylation Reaction of Proton-Containing Nucleophiles

2018 ◽  
Vol 43 (2) ◽  
pp. 121-135 ◽  
Author(s):  
Stanislav Bakhtin ◽  
Elena Shved ◽  
Yuliia Bespal'ko ◽  
Yuliia Stepanova
Keyword(s):  
Quantum Chemical ◽  
Ring Opening ◽  
Uv Spectroscopy ◽  
Activation Parameters ◽  
Oxirane Ring ◽  
Acetate Anion ◽  
Reactive Intermediate ◽  
Model Base ◽  
Organic Bases ◽  
Initial Base

The mechanism of action of nucleophilic and non-nucleophilic bases in the system “acetic acid (HOAc) – epichlorohydrin (ECH) – R3X (R = alkyl, X = N, P)” has been studied. The observed orders of the reaction with respect to the components were found. It has been proved that the catalytic activity of the starting bases is determined by their nucleophilicity, rather than basicity. It is shown that the crucial stage of the reaction is the quaternisation of the starting base with the formation of a reactive intermediate, the acetate anion. Monitoring of possible paths of oxirane ring-opening by the initial base and the acetate anion was carried out. The behaviour of the model base, triphenylphosphine, in the quaternisation reaction was studied by UV spectroscopy. The rate constants of quaternisation in the reaction of tribenzylamine and triphenylphosphine with ECH have been estimated. The activation parameters of the stages of oxirane ring-opening by trimethylamine and the acetate anion were calculated using a quantum chemical method. It has been shown that the starting base attacks only the activated oxirane, while the acetate anion is capable of nucleophilic opening of both activated and non-activated ECH rings. A scheme for the catalytic opening of the oxirane ring by the bases in the system “ECH – HOAc – R3X” is proposed, which includes a series of both consecutive and parallel stages leading to the formation of the reaction product.

scholarly journals Phosphorylated cyclopropanes in the synthesis of α-alkylidene-γ-butyrolactones: total synthesis of (±)-savinin, (±)-gadain and (±)-peperomin E

2016 ◽  
Vol 14 (38) ◽  
pp. 8971-8988 ◽  
Author(s):  
Matthew G. Lloyd ◽  
Richard J. K. Taylor ◽  
William P. Unsworth
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Ring Opening

A novel telescoped cyclopropanation/reductive ring-opening/olefination sequence is reported for the synthesis of α-alkylidene-γ-butyrolactone natural products.

Sign in / Sign up

Export Citation Format

Share Document