ISSN:
0009-2940
Keywords:
Bissecododecahedranes, saturated, unsaturated
;
Homoconjugation
;
Hyperstability
;
Addition reactions
;
Cage effects
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
In bissecododecahedra-1,10(11)-dienes, the syn-periplanar and unusually proximate arrangement of the π bonds is responsible for extraordinary physical properties such as strong throughspace homoconjugation, low oxidation potentials, and a special reactivity pattern. In pursuit of route B to dodecahedranes[1], the hyperstability predicted (MM2) for these bissecodienes and the related monoenes has been experimentally verified only for the latter in their resistance towards catalytic hydrogenation. Non-hydrogenative saturation of (3,8-difunctionalized) bissecodienes (3, 8, 13) and monoenes (4, 9, 14) becomes increasingly hampered due to the increased steric congestion on the more spherical molecular surfaces but can be achieved in „high-driving-force” reactions [cis-hydroxylation (26, 27, 41, 42), epoxidation (38, 54, 57, 58, 60, 63, 80, 83), cyclopropanation (55, 59, 61, 64]. In contrast, cycloadditive four-, five- (73), and six-membered (76) ring annulation again is limited to monoadditions. The half-cages in the bissecododecahedrane structures provide for remarkable steric steering and protection [e.g. anti-selective protonation (alkylation) of carbanions 57a (84a)2-, lack of hydrazone formation from ketones 58, 89, resistance of syn-bis(acid chloride) 86 towards hydrolysis.
Additional Material:
9 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19921250728
