Efficient Entry into 2-Substituted Tetrahydroquinoline Systems through Alkylative Ring Expansion: Stereoselective Formal Synthesis of (±)-Martinellic Acid

2010 ◽  
Vol 75 (3) ◽  
pp. 914-921 ◽  
Author(s):  
Masafumi Ueda ◽  
Sayuri Kawai ◽  
Masataka Hayashi ◽  
Takeaki Naito ◽  
Okiko Miyata
Keyword(s):  
Ring Expansion ◽  
Formal Synthesis ◽  
Martinellic Acid

Diels–Alder approach to (±)-longifolene: A formal synthesis

1992 ◽  
Vol 70 (5) ◽  
pp. 1375-1384 ◽  
Author(s):  
Tse-Lok Ho ◽  
Wen-Lung Yeh ◽  
John Yule ◽  
Hsing-Jang Liu
Keyword(s):  
Maleic Anhydride ◽  
Ring Expansion ◽  
Alder Reaction ◽  
Diels Alder ◽  
Formal Synthesis ◽  
Racemic Form ◽  
Diels Alder Reaction ◽  
Key Steps

A formal synthesis of longifolene in racemic form is concluded starting from the Diels–Alder reaction of 6,6-di-methylfulvene and maleic anhydride. Key steps are cyclodehydration, conjugate methylation, and ring expansion.

scholarly journals Enantioselective ring expansion of prolinols and ring-closing metathesis: formal synthesis of (-)-swainsonine

ARKIVOC ◽  
2006 ◽  
Vol 2007 (5) ◽  
pp. 38-45
Author(s):  
Ingrid Déchamps ◽  
Domingo Gomez Pardo ◽  
Janine Cossy
Keyword(s):  
Ring Expansion ◽  
Ring Closing Metathesis ◽  
Formal Synthesis

Synthesis, Structure and Reactivities of Pentacoordinated Phosphorus–Boron Bonded Compounds

2020 ◽  
Author(s):  
Nathan O'Brien ◽  
Naokazu Kano ◽  
Nizam Havare ◽  
Ryohei Uematsu ◽  
Romain Ramozzi ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Ring Expansion ◽  
Bicyclic Compound ◽  
Compound A ◽  
Ligand System ◽  
Large Bulk ◽  
Rearrangement Reaction ◽  
Hydride Abstraction ◽  
Pentacoordinated Phosphorus ◽  
Acids And Bases

<div>The isolation and reactivities of two pentacoordinated phosphorus–tetracoordinated boron bonded compounds were</div><div>explored. A strong Lewis acidic boron reagent and electron-withdrawing ligand system were required to form the</div><div>pentacoordinated phosphorus state of the P–B bond. The first compound, a phosphoranyl-trihydroborate, gave a THF</div><div>stabilised phosphoranyl-borane intermediate upon a single hydride abstraction in THF. This compound could undergo a</div><div>unique rearrangement reaction, that involved a two-fold ring expansion, to give an unusual fused bicyclic compound or it</div><div>could act as a mono-hydroboration reagent. The hydroboration reactivity of the intermediate was found to be more reactive</div><div>towards alkynes over alkenes with good to moderate regioselectivity towards the terminal carbon. The second compound,</div><div>a phosphoranyl-triarylborate, was found to have a vastly different reactivity to the trihydroborate as it was highly stable</div><div>towards acids and bases. This is thought to be due to the large bulk around the P–B bond as shown in the crystal structure</div>

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