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In order to determine the product selectivity , such
as the diastereoselectivity , periselectivity and
regioselectivity ,which is governed by steric effect or by
stabilizing secondaryorbital interactions of the exocyclic
substituents on the 8-aryl-8-azaheptafulvenes , the
intermolecular cycloadditionsof asymmetrically
substituted and symmetrically di-substituted fulvenes
with 8-aryl-8-azaheptafulvenes areinvestigated . The
intermolecular cycloaddition reactions of 8-aryl-8-
azaheptafulvenes with 6,6-dimethylfulvene in
refluxingbenzene , give only Anti-[6+4] ( E forms anrd
Z forms ) cycloadducts 2-2(E) , 2-2(Z) , 2-4(E) , 2-4(Z) ~
2-11(Z)' .When the reaction was carried out in
refluxing xylene ,Anti-[6+4] ( E forms and Z forms )
cycloadducts werealso observed . No cycloaddition
reaction was observedwhen the balky exocyclic
substituted 6-t-butyl-6-methylfulvene ( 5 , page 95 )
was reacted with 8-aryl-8-azaheptafulvenes .
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