Preparation of cyclic α-(3,4-dihydro-2-isopropyl-4-oxoquinazolin-3-yl)amino-β-ketoesters: Further oxidation with lead tetra-acetate in dichloromethane and in methanol leading to ring-expansion and ring-cleavage products, respectively

1994 ◽  
Vol 35 (41) ◽  
pp. 7863-7866 ◽  
Author(s):  
R Atkinson
Keyword(s):  
Ring Expansion ◽  
Ring Cleavage ◽  
Lead Tetra Acetate

Highly regioselective hypervalent iodine mediated ring cleavage and ring expansion reactions of some pentacyclo[5.4.0.02,6.03,10.05,9]undecane derivatives

Tetrahedron ◽  
1995 ◽  
Vol 51 (43) ◽  
pp. 11673-11680 ◽  
Author(s):  
Alan P. Marchand ◽  
D Rajagopal ◽  
Andrew Burritt ◽  
Simon G. Bott ◽  
William H. Watson ◽  
...  
Keyword(s):  
Ring Expansion ◽  
Ring Cleavage ◽  
Hypervalent Iodine

ChemInform Abstract: Highly Regioselective Hypervalent Iodine-Mediated Ring Cleavage and Ring Expansion Reactions of Some Pentacyclo(5.4.0.02,6.03,10.05,9) undecane Derivatives.

ChemInform ◽  
2010 ◽  
Vol 27 (9) ◽  
pp. no-no
Author(s):  
A. P. MARCHAND ◽  
D. RAJAGOPAL ◽  
A. BURRITT ◽  
S. G. BOTT ◽  
W. H. WATSON ◽  
...  
Keyword(s):  
Ring Expansion ◽  
Ring Cleavage ◽  
Hypervalent Iodine

Ring cleavage and ring expansion of indoles by superoxide ion

1982 ◽  
Vol 23 (43) ◽  
pp. 4473-4476 ◽  
Author(s):  
É. Balogh-Hergovich ◽  
G. Speier
Keyword(s):  
Ring Expansion ◽  
Ring Cleavage ◽  
Superoxide Ion

Studies in the Cycloproparene Series: Reactions of Alkylidenecycloproparenes With Electrophiles

1987 ◽  
Vol 40 (8) ◽  
pp. 1375 ◽  
Author(s):  
SJ Buckland ◽  
B Halton ◽  
Q Mei ◽  
PJ Stang
Keyword(s):  
Acetic Acid ◽  
Ring Expansion ◽  
Membered Ring ◽  
Ring Cleavage ◽  
Vinyl Ethers ◽  
Subsequent Reaction ◽  
Bromine Water ◽  
Delicate Balance ◽  
Counter Ion ◽  
Anhydrous Acetic Acid

The addition of an electrophile to the alkylidenecycloproparenes (2a-d) is dominated by capture at the exocyclic centre with formation of the corresponding cycloproparenyl cation, e.g. (15). Subsequent reaction with the counter ion is usually accompanied by cleavage of the three-membered ring. Thus compounds (2) give the ethanones (4) with aqueous acids whilst anhydrous acetic acid yields the vinyl acetates (5). Silver(1)-catalysed methanolysis of (2) leads to vinyl ethers (6); the alkyne (7) is formed only from (2d) which carries a vinylic proton. Brominations and bromine water additions lead to products of ring expansion (8)-(10) or ring cleavage (11)-(14) depending upon the conditions employed. These latter reactions demonstrate a delicate balance between cycloproparenylcarbinyl cation formation and cleavage of the three-membered ring.

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