Chemical Consequences of Long-Range Orbital Interactions in Norbornane-1,4-diol Monosulfonate Esters

Article abstract of DOI:10.1021/jo00118a046

Seven monotosylated 1,4-diols with the rigid norbornane skeleton were treated with a strong base in refluxing benzene to find out whether these compounds react by initial heterolysis of the tosylate ester bond induced by long-range orbital interactions.The tosylates 1-7 were designed to investigate the influence of the ?-relay (U-, sickle-, or W-shaped) between the donor and acceptor end of the system, to check whether primary carbocationic ion pairs could act as intermediates, and to study conformational influences on reactivity and product formation.Tosylate 1 with a U-like arrangement of the ?-relay reacted relatively slowly and followed reaction pathways in which no long-range orbital interactions are involved.The reaction outcome of tosylate 2 which possesses a sickle-like arrangement of the ?-relay indicates two competitive processes with and without the involvement of long-range orbital interactions.The secondary tosylates 3, 6, and 7 which all possess a W-like arrangement reacted relatively fast and showed predominantly homofragmentation.Although an ideal W-like arrangement is present in the primary tosylates 4 and 5, no reactions in which long-range orbital interactions are involved were observed.The tosylates 6 and 7 in which the tosylate group is conformationally mobile can give rise to mixtures of products.The ratio in which these products are formed can be rationalized by using the Curtin-Hammett principle.