ChemInform Abstract: Ring Expansion vs. Cleavage of the Exocyclic Double Bond of 2-Cycloalkylidenedihydrobenzothiazoles and -benzimidazoles by Methanesulfonyl Azide.

ChemInform ◽  
2010 ◽  
Vol 31 (24) ◽  
pp. no-no
Author(s):  
Helmut Quast ◽  
Svetlana Ivanova
Keyword(s):  
Double Bond ◽  
Ring Expansion ◽  
Exocyclic Double Bond

scholarly journals Stereoselective total syntheses of (±)-sinularene and (±)-5-epi-sinularene: a general intramolecular Diels–Alder approach to tricyclic sesquiterpenes

1985 ◽  
Vol 63 (4) ◽  
pp. 993-995 ◽  
Author(s):  
Kazimierz Antczak ◽  
John F. Kingston ◽  
Alex G. Fallis
Keyword(s):  
Double Bond ◽  
Methyl Ester ◽  
Total Synthesis ◽  
Ring System ◽  
Diels Alder ◽  
Exocyclic Double Bond ◽  
Total Syntheses ◽  
Methyl Group ◽  
Secondary Hydroxyl ◽  
Selective Hydrogenolysis

Stereoselective total synthesis of (±)-sinularene and (±)-5-epi-sinularene are described. The sequence employs a "blocked" cyclopentadiene in which the cyclopropane unit also serves as a latent methyl group. Thus intramolecular [4 + 2] cycloaddition of the substituted methyl spiro[2.4]hepta-4,6-dien-1-yl)-2-pentenoate 11 affords 5-benzyloxy-6-isopropyl-8-carbomethoxytetracyclo[5.4.01,7.02,4.02,9]undec-10-ene (12) which after selective hydrogenolysis generates the tricyclo[4.4.01,6.02,8]decane (sinularene) ring system. Removal of the secondary hydroxyl function (Ph3P/CCl4/CH3CN; H2/Pd/C), reduction of the methyl ester (LiAlH4), and introduction of the exocyclic double bond (acetate pyrolysis, 550 °C) completes the synthesis of (±)-sinularene in 14 steps from cyclopentadiene. A parallel series of reactions employing the isopropyl epimer of 12 affords (±)-5-epi-sinularene.

Formation of Dihydroaza-azulanones Possessing Spirocyclic Moieties: [8+2] Type Cycloaddition Reactions of Iminotropones to an Exocyclic Double Bond of 8-Oxoheptafulvene

Heterocycles ◽  
1995 ◽  
Vol 41 (10) ◽  
pp. 2181 ◽  
Author(s):  
Katsuhiro Saito ◽  
Yuka Saito ◽  
Masayuki Tomita ◽  
Hiroshi Taniguchi ◽  
Hirofumi Okabayashi
Keyword(s):  
Double Bond ◽  
Exocyclic Double Bond ◽  
Cycloaddition Reactions

Structurally original oxathioethers macrocycles containing an exocyclic double-bond: synthesis, characterization, reactivity, and coordination

Tetrahedron ◽  
2014 ◽  
Vol 70 (35) ◽  
pp. 5650-5658 ◽  
Author(s):  
Guillaume Carel ◽  
Alina Saponar ◽  
Nathalie Saffon ◽  
Marc Vedrenne ◽  
Stéphane Massou ◽  
...  
Keyword(s):  
Double Bond ◽  
Exocyclic Double Bond

ChemInform Abstract: SYNTHESIS OF CYCLIC IMINES HAVING A CONJUGATED EXOCYCLIC DOUBLE BOND

1984 ◽  
Vol 15 (3) ◽  
Author(s):  
Y. NOMURA ◽  
T. BANDO ◽  
Y. TAKEUCHI ◽  
S. TOMODA
Keyword(s):  
Double Bond ◽  
Exocyclic Double Bond

Reactions of primulagenin A. IV. Ring expansion in Oleana-12,15-diene-3b,28-diol and the related 13(18),15-diene isomer

1980 ◽  
Vol 33 (11) ◽  
pp. 2517 ◽  
Author(s):  
OD Hensens ◽  
KG Lewis ◽  
DJ Tucker
Keyword(s):  
Double Bond ◽  
Sulfonyl Chloride ◽  
Ring Expansion ◽  
Pyridine Solution ◽  
Bond Isomer

Treatment of oleana-12,15-diene-3β,28-diol 3-acetate with a cold pyridine solution of p-toluene-sulfonyl chloride leads to expansion of ring D with the formation of 28-nor-D(16a)-homo-oleana-12,15,17(18)- trien-3β-yl acetate (7). Under more vigorous conditions a mixture of the D-homo compound (7) and a double bond isomer (11) is obtained. Subjection of oleana-13(18),15-diene-3β,28- diol 3-acetate to similar reflux conditions also forms the D-homo compound (7).

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