π-Facial stereoselectivity in the Diels–Alder reactions of a rigid carbocyclic diene: spiro(bicyclo[2.2.1]heptane-2,1′-[2,4]cyclopentadiene)

1991 ◽  
Vol 69 (1) ◽  
pp. 179-184 ◽  
Author(s):  
D. Jean Burnell ◽  
Zdenek Valenta
Keyword(s):  
Transition State ◽  
Key Words ◽  
Diels Alder ◽  
Steric Interactions

The plane-nonsymmetrical diene spiro(bicyclo[2.2.1]heptane-2,1′-[2,4]cyclopentadiene) (2) was synthesized, and the π-facial stereoselectivity of its Diels–Alder cycloadditions with three cyclic dienophiles was examined. Adduct ratios were very similar, and the selectivity is surmised to be mainly the result of steric interactions at the transition state. Key words: facial stereoselectivity, Diels–Alder, cycloaddition.

Ab initio Cs transition state for the Diels-Alder reaction of acetylene and butadiene

1990 ◽  
Vol 55 (12) ◽  
pp. 3804-3807 ◽  
Author(s):  
James M. Coxon ◽  
Stephen T. Grice ◽  
Robert G. A. R. Maclagan ◽  
D. Quentin McDonald
Keyword(s):  
Transition State ◽  
Ab Initio ◽  
Alder Reaction ◽  
Diels Alder ◽  
Diels Alder Reaction

ChemInform Abstract: First Evidence of a Chair-Boat-Boat Transition State in the Transannular Diels-Alder Reaction.

ChemInform ◽  
2010 ◽  
Vol 25 (38) ◽  
pp. no-no
Author(s):  
Y. L. DORY ◽  
C. OUELLET ◽  
S. BERTHIAUME ◽  
A. FAVRE ◽  
P. DESLONGCHAMPS
Keyword(s):  
Transition State ◽  
Alder Reaction ◽  
Diels Alder ◽  
Diels Alder Reaction

Acyl cyanides as carbonyl heterodienophiles: application to the synthesis of naphthols, isoquinolones, and isocoumarins

1996 ◽  
Vol 74 (2) ◽  
pp. 221-226 ◽  
Author(s):  
Richard Connors ◽  
Elisabeth Tran ◽  
Tony Durst
Keyword(s):  
Key Words ◽  
Diels Alder ◽  
Acetonitrile Solution ◽  
Carbon And Nitrogen ◽  
Nitrogen Nucleophiles ◽  
Derivatives Of

Irradiation of 2-methylbenzoyl cyanide (3a) in acetonitrile solution results in the formation of its dimer, which upon loss of HCN gives rise to the cycloadduct 7a. The dimerization also proceeds efficiently with derivatives of 3a giving adducts 7b and 7c. When 2-methylaroyl cyanides are photolyzed in the presence of a more reactive acyl cyanide the mixed adducts 8a–e are obtained in excellent yields. The cycloadducts 7a–c and 8a–e react with carbon and nitrogen nucleophiles by a tandem addition–cyclization sequence furnishing substituted naphthols (10a and 10b) and isoquinolones (11a–d), respectively. Isocoumarins 12a and 12b were prepared from the adducts 8a and 8e by treatment with potassium tert-butoxide in THF. Key words: naphthols, isoquinolones, isocoumarins, synthesis of; acyl cyanides; hetero Diels–Alder.

REACTIONS OF SUGAR CHLOROSULFATES: VII. SOME CONFORMATIONAL ASPECTS

1966 ◽  
Vol 44 (13) ◽  
pp. 1483-1491 ◽  
Author(s):  
A. G. Cottrell ◽  
E. Buncel ◽  
J. K. N. Jones
Keyword(s):  
Transition State ◽  
Sulfuryl Chloride ◽  
Reaction Conditions ◽  
Steric Interactions

The reaction of sulfuryl chloride with several 1,6-anhydro-hexosans has yielded crystalline, fully chlorosulfated derivatives. Replacement of the chlorosulfate moieties by chlorodeoxy groups could not be achieved under the reaction conditions employed. This non-reactivity is discussed in terms of steric interactions in the transition state for substitution.An examination of some chloro-substituted sugar chlorosulfates confirmed that an axial chlorodeoxy group in a glycopyranoside deactivates a neighboring equatorial chlorosulfate group and thus prevents further chlorodeoxy groups being introduced into such positions. Methyl α-D-altropyranoside, methyl α-L-rhamnopyranoside, methyl α-D-lyxopyranoside, L-rhamnose, and D-lyxose were reacted with sulfuryl chloride. The resulting products were those expected if these sugars reacted primarily in the C1 conformation.

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