scholarly journals Heteroareno-annelated estranes by triene cyclization

2006 ◽  
Vol 4 (3) ◽  
pp. 375-402 ◽  
Author(s):  
Masataka Watanabe ◽  
Taisuke Matsumoto ◽  
Shuntaro Mataka ◽  
Thies Thiemann
Keyword(s):  
Intramolecular Cyclization ◽  
Cross Coupling ◽  
One Pot ◽  
Wittig Olefination ◽  
Olefination Reactions

Abstract17-Thienyl-and 17-benzo[b]thienyl-3-hydroxyestra-1,3,5(10),16-tetraenes were synthesized by either sequential or one-pot Suzuki cross-coupling and Wittig olefination reactions. At 160 °C, heteroaryl substituted steroids were observed to undergo thermal intramolecular cyclization to produce E-ring heteroareno-annelated estranes.

scholarly journals Facile Access to Condensed Arenothiophenes – Preparation of Dihydrophenanthrothiophenes and Dihydrophenanthro[1]Benzothiophenes

2005 ◽  
Vol 2005 (9) ◽  
pp. 564-571 ◽  
Author(s):  
Masataka Watanabe ◽  
Taisuke Matsumoto ◽  
Shuntaro Mataka ◽  
Thies Thiemann
Keyword(s):  
Structural Analysis ◽  
Cross Coupling ◽  
One Pot ◽  
X Ray ◽  
Wittig Olefination ◽  
Crystal Structural

4-Bromo-3-formyl-1,2-dihydronaphthalenes undergo Suzuki cross coupling and Wittig olefination reaction in a one pot procedure. The trienes obtained can be cyclised thermally under concomitant dehydrogenation to dihydrophenanthrothiophenes and dihydrophenanthro[1]benzothiophenes. An X-ray crystal structural analysis was carried out for ethyl (E)-3-[1-(1-benzothiophen-3-yl)-3,4-dihydro-2-naphthyl]propenoate.

scholarly journals Solvent reduced wittig olefination reactions with halo containing conjugated phosphoranes

2006 ◽  
Vol 4 (3) ◽  
Author(s):  
Thies Thiemann ◽  
Yasuko Tanaka ◽  
Keiko Ideta ◽  
Shuntaro Mataka
Keyword(s):  
Wittig Reaction ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Analogous Reaction ◽  
Cross Coupling Reaction ◽  
Wittig Olefination ◽  
Olefination Reactions

AbstractThe Wittig reaction of carbaldehydes with alkoxycarbonylhalomethylidenetriphenylphosphoranes can be performed with ease in solventless systems. The analogous reaction of carbaldehydes with acylhalomethylidenetriphenylphosphoranes requires a small amount of solvent, such as chloroform, in order for the reaction to proceed. The products of the reaction are versatile precursors for further transformations, such as the Suzuki-Miyaura cross-coupling reaction.

Efficient Access to Original 6-Substituted 5-Nitro-2,3-dihydro­imidazo[2,1-b]oxazoles

Synthesis ◽  
2017 ◽  
Vol 49 (12) ◽  
pp. 2775-2785 ◽  
Author(s):  
Fanny Mathias ◽  
Youssef Kabri ◽  
Maxime Crozet ◽  
Patrice Vanelle
Keyword(s):  
Intramolecular Cyclization ◽  
Bromine Atom ◽  
Cross Coupling ◽  
Sonogashira Reaction ◽  
Coupling Reactions ◽  
One Pot ◽  
Cross Coupling Reactions ◽  
Efficient Access ◽  
Palladium Catalyzed ◽  
Hydroxyethyl Group

A one-pot sequential intramolecular cyclization and Suzuki–Miyaura or Sonogashira reaction under microwave irradiation are reported in the 5-nitro-2,3-dihydroimidazo[2,1-b]oxazole series. The intramolecular cyclization of 1-(2,4-dibromo-5-nitro-1H-imidazol-1-yl)propan-2-ol between the hydroxyethyl group and the bromine atom at the 2-position is carried out first, followed by optimization and generalization of the Suzuki–Miyaura and Sonogashira cross-coupling reactions of the bromine atom at the 4-position. The various boronic acids and alkynyl derivatives used to perform these palladium-catalyzed cross-coupling reactions allowed to substitute the 6-position of 5-nitro-2,3-dihydroimidazo[2,1-b]oxazole compounds.

scholarly journals Post-Polymerization Modification of Ring Opening Metathesis Polymerization (ROMP)-Derived Materials Using Wittig Reactions

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1247
Author(s):  
Ryan Duty ◽  
Christopher E. Hobbs
Keyword(s):  
Ring Opening ◽  
Phosphonium Salt ◽  
Cross Linking ◽  
Ring Opening Metathesis Polymerization ◽  
One Pot ◽  
Metathesis Polymerization ◽  
Aryl Aldehydes ◽  
Wittig Olefination ◽  
Wittig Reactions ◽  
Olefination Reactions

This communication describes our recent efforts to utilize Wittig olefination reactions for the post-polymerization modification of polynorbornene derivatives prepared through ring opening metathesis polymerization (ROMP). Polymerizing α-bromo ester-containing norbornenes provides polymers that can undergo facile substitution with triphenylphosphine. The resulting polymeric phosphonium salt is then deprotonated to form an ylide that undergoes reaction with various aryl aldehydes in a one-pot fashion to yield the respective cinnamates. These materials can undergo further modification through photo-induced [2 + 2] cycloaddition cross-linking reactions.

One pot Suzuki coupling - Wittig olefination reactions

2004 ◽  
Vol 2004 (11) ◽  
pp. 723-727 ◽  
Author(s):  
Thies Thiemann ◽  
Masataka Watanabe ◽  
Yasuko Tanaka ◽  
Shuntaro Mataka
Keyword(s):  
Suzuki Coupling ◽  
One Pot ◽  
Wittig Olefination ◽  
Olefination Reactions

Combined Suzuki Coupling – Wittig Olefination Reaction in Aqueous Medium

2005 ◽  
Vol 60 (12) ◽  
pp. 1299-1307 ◽  
Author(s):  
Kyoko Yamamoto ◽  
Masataka Watanabe ◽  
Kyoko Ideta ◽  
Shuntaro Mataka ◽  
Thies Thiemann
Keyword(s):  
Aqueous Medium ◽  
Cross Coupling ◽  
Suzuki Coupling ◽  
One Pot ◽  
Wittig Olefination

Bromoarene carbaldehydes and bromoheteroarene carbaldehydes underwent a one-pot Suzuki cross coupling and Wittig olefination in aqueous medium to give compounds with extended π-systems.

One-Pot Suzuki Coupling — Wittig Olefination Reactions.

ChemInform ◽  
2005 ◽  
Vol 36 (27) ◽  
Author(s):  
Thies Thiemann ◽  
Masataka Watanabe ◽  
Yasuko Tanaka ◽  
Shuntaro Mataka
Keyword(s):  
Suzuki Coupling ◽  
One Pot ◽  
Wittig Olefination ◽  
Olefination Reactions

One-pot access to 2-oxazolines via a Castro-Stephens coupling and intramolecular cyclization

2021 ◽  
Vol 08 ◽  
Author(s):  
Dnyaneshwar Nighot ◽  
Arvind Kumar Jain ◽  
Imran Ali ◽  
Varun Rawat
Keyword(s):  
Organic Chemistry ◽  
Biological Activity ◽  
Intramolecular Cyclization ◽  
Heterocyclic Compounds ◽  
Cross Coupling ◽  
One Pot ◽  
Alcohol Group ◽  
Xrd Studies ◽  
Oxazoline Derivatives

Aim: Here, we have reported easy one-pot access to a series of oxazolines using a modified Castro-Stephens coupling protocol. Background: 2-oxazolines have been shown to have significant biological activity and wide-ranging applications in organic chemistry. These properties make oxazolines as heterocyclic compounds of immense importance. Objective: The objective of this study is to synthesize oxazoline derivatives via an economical and one-pot protocol. Method: 2-oxazoline has been synthesized through Cu-powder mediated Castro-Stephens coupling and intramolecular cyclization route. The mechanism involves a rearrangement in which one of the oxygen from the N-acylamino alcohol group is liberated as water and then transferred to alkyne functionality to form 2-oxazoline derivatives. The oxazolines were characterized by NMR, mass, and XRD studies. Result: The protocol is economically viable and uses readily available Cu-powder along with DMF for cross-coupling and cyclization steps.

Concise Synthesis of GB22 by Endo-Selective Siloxycyclopropane Arylation

2019 ◽  
Author(s):  
Hannah E. Burdge ◽  
Takuya Oguma ◽  
Takahiro Kawajiri ◽  
Ryan Shenvi
Keyword(s):  
Intramolecular Cyclization ◽  
Cross Coupling ◽  
Building Blocks ◽  
Ring Expansion ◽  
Dual Catalysis ◽  
Acid Labile

<div><div><div><p>The first synthesis of GB22 was accomplished by a con- cise, modular route. Two building blocks converged in a novel sp3-sp2 attached-ring coupling that used Ir/Ni dual-catalysis to reverse the regioselectivity of siloxycy- clopropane arylation. This cross-coupling proved general to access β-substituted tetralones via ring-expansion of indanone-derived siloxycyclopropanes. The congested, bridging rings of the GB alkaloids were completed using an aluminum-HFIP complex that effected intramolecular cyclization of an acid-labile substrate.</p></div></div></div>

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