scholarly journals Synthesis of Dihydropyrano[3,2-c]pyrazoles via Double Bond Migration and Ring-Closing Metathesis

Molecules ◽  
2019 ◽  
Vol 24 (2) ◽  
pp. 296 ◽  
Author(s):  
Yoshihide Usami ◽  
Kodai Sumimoto ◽  
Azusa Kishima ◽  
Yuya Tatsui ◽  
Hiroki Yoneyama ◽  
...  
Keyword(s):  
Double Bond ◽  
Claisen Rearrangement ◽  
Ring Closing Metathesis ◽  
Double Bond Migration ◽  
Ruthenium Hydride

Three types of pyrazole-fused heterobicycles, i.e., 1,5-, 1,7-, and 2,5-dihydropyrano[3,2-c]pyrazoles, were synthesized from 4-allyloxy-1H-pyrazoles. A sequence of the Claisen rearrangement of 4-allyloxy-1H-pyrazoles, ruthenium-hydride-catalyzed double bond migration, O-allylation, and ring-closing metathesis was employed in this study.

scholarly journals Ring-closing-metathesis-based synthesis of annellated coumarins from 8-allylcoumarins

2018 ◽  
Vol 14 ◽  
pp. 2991-2998 ◽  
Author(s):  
Christiane Schultze ◽  
Bernd Schmidt
Keyword(s):  
Double Bond ◽  
Olefin Metathesis ◽  
Claisen Rearrangement ◽  
Allylic Oxidation ◽  
Allyl Ether ◽  
Ring Closing Metathesis ◽  
Wittig Olefination

8-Allylcoumarins are conveniently accessible through a microwave-promoted tandem Claisen rearrangement/Wittig olefination/cyclization sequence. They serve as a versatile platform for the annellation of five- to seven-membered rings using ring-closing olefin metathesis (RCM). Furano-, pyrano-, oxepino- and azepinocoumarins were synthesized from the same set of precursors using Ru-catalyzed double bond isomerizations and RCM in a defined order. One class of products, pyrano[2,3-f]chromene-2,8-diones, were inaccessible through direct RCM of an acrylate, but became available from the analogous allyl ether via an assisted tandem catalytic RCM/allylic oxidation sequence.

Chiron approach for the total synthesis of brevipolide M

Synlett ◽  
2022 ◽  
Author(s):  
Yang Liu ◽  
Ziyang Zhao ◽  
Chao Hu ◽  
Chuanfang Zhao ◽  
Jun Liu ◽  
...  
Keyword(s):  
Double Bond ◽  
Total Synthesis ◽  
Stereoselective Synthesis ◽  
Ring Closing Metathesis ◽  
One Pot ◽  
Double Bond Migration ◽  
Key Steps

An efficient stereoselective synthesis of brevipolide M was established in 13 linear steps and 17.8% overall yields base on chiron approach. The key steps of our synthesis involved tandem homologation / tetrahydrofuran cyclization and sequential ring-closing metathesis (RCM) / double-bond migration in one-pot processes.

The role of the functional group in double bond migration in allylic systems catalysed by ruthenium hydride complexes

2006 ◽  
Vol 253 (1-2) ◽  
pp. 132-146 ◽  
Author(s):  
S. Krompiec ◽  
N. Kuźnik ◽  
M. Krompiec ◽  
R. Penczek ◽  
J. Mrzigod ◽  
...  
Keyword(s):  
Double Bond ◽  
Functional Group ◽  
Double Bond Migration ◽  
Ruthenium Hydride ◽  
Hydride Complexes

RUTHENIUM HYDRIDE-CATALYZED DOUBLE BOND MIGRATION OF 2,5-DIMETHOXY-2,5-DIHYDROFURANS. A NEW PROCESS FOR THE PREPARATION OF γ-KETOESTERS

1982 ◽  
Vol 11 (1) ◽  
pp. 23-26 ◽  
Author(s):  
Kenji Hirai ◽  
Hiroharu Suzuki ◽  
Hiroshi Kashiwagi ◽  
Yoshihiko Moro-Oka ◽  
Tsuneo Ikawa
Keyword(s):  
Double Bond ◽  
Double Bond Migration ◽  
Ruthenium Hydride ◽  
New Process

Sequential olefin metathesis — Intramolecular asymmetric Heck reactions in the synthesis of polycycles

2004 ◽  
Vol 82 (2) ◽  
pp. 399-407 ◽  
Author(s):  
Mark Lautens ◽  
Valentin Zunic
Keyword(s):  
Double Bond ◽  
Heck Reaction ◽  
Olefin Metathesis ◽  
Heck Reactions ◽  
Ring Closing Metathesis ◽  
Double Bond Migration ◽  
Double Ring ◽  
Asymmetric Heck Reaction

Application of the intramolecular asymmetric Heck reaction in the desymmetrization of a novel class of symmetrical bicyclodienes, synthesized through a diastereoselective double ring-closing metathesis (DSRCM) reaction, was achieved with good yields (approximately 80%) and excellent enantioselectivities (up to 99% ee). Three contiguous stereocenters are established in a single desymmetrization reaction. The use of thallium carbonate as base in the asymmetric Heck reaction favours double bond migration in 13. Cationic conditions delivered products with good to excellent enantioselectivities, surpassing the results under neutral conditions.Key words: asymmetric, Heck, polycycles, metathesis, stereoselective, desymmetrization.

The Role of the Functional Group in Double Bond Migration of Allylic Systems Catalyzed by Ruthenium Hydride Complexes

ChemInform ◽  
2007 ◽  
Vol 38 (25) ◽  
Author(s):  
S. Krompiec ◽  
N. Kuznik ◽  
M. Krompiec ◽  
R. Penczek ◽  
J. Mrzigod ◽  
...  
Keyword(s):  
Double Bond ◽  
Functional Group ◽  
Double Bond Migration ◽  
Ruthenium Hydride ◽  
Hydride Complexes

Synthesis of a Simplified Analogue of Eleutherobin via a Claisen Rearrangement and Ring Closing Metathesis Strategy.

ChemInform ◽  
2005 ◽  
Vol 36 (35) ◽  
Author(s):  
Gary C. H. Chiang ◽  
Andrew D. Bond ◽  
Andrew Ayscough ◽  
Gilles Pain ◽  
Sylvie Ducki ◽  
...  
Keyword(s):  
Claisen Rearrangement ◽  
Ring Closing Metathesis
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