Conformational analysis of 1,4-cyclohexadienes. A shallow boat-shaped 1,4-dihydronaphthalene
The metal/ammonia reduction of 7,12-dihydropleiadene affords 3,7,12a,12-tetrahydropleiadene which models indicate can exist in one of three different conformations (or in a dynamic equilibrium). Two of these conformers possess fully-puckered, boat-shaped 1,4-dihydronaphthalene units (5a and 5b) whereas the third (5c) incorporates a flattened six-membered ring. This latter conformation is the favored one as deduced by a variety of NMR techniques and is also predicted by MM2 force field calculations. The NMR parameters from 5c are then applied to stereochemical problems associated with a number of previously investigated 1-R-1,4-dihydronaphthalenes (R = CO/sub 2/H, Ph, CH/sub 2/OH, or C(CH/sub 3/)/sub 2/OH). MM2 results are also presented for the entire sequence. It is concluded that flattened boat conformations are expected to be common for many 1-R-1,4-dihydronaphthalenes. 15 references, 2 figures, 2 tables.
- Research Organization:
- Indiana Univ.-Purdue Univ., Indianapolis
- OSTI ID:
- 5814931
- Journal Information:
- J. Org. Chem.; (United States), Journal Name: J. Org. Chem.; (United States) Vol. 50:26; ISSN JOCEA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400301* -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
ALKENES
CONFIGURATION
CONFORMATIONAL CHANGES
COUPLING CONSTANTS
CYCLOALKENES
DATA
EXPERIMENTAL DATA
HEXENES
HYDROCARBONS
INFORMATION
MAGNETIC RESONANCE
NMR SPECTRA
NUCLEAR MAGNETIC RESONANCE
NUMERICAL DATA
ORGANIC COMPOUNDS
RESONANCE
SPECTRA
STEREOCHEMISTRY