| Abstract
| - The pericyclic reactions of 2,5-bis(methoxycarbonyl)-3,4-diphenylcyclopentadienone (1a) with bothallylic and propargylic amines have been investigated. The reaction proceeded via initial formationof the 1,4 adducts followed by the ene cyclization and/or sequential pericyclic reactions dependingupon the structures of the amines. The reaction of 1a with diallylamine (2a) gave the tetracycliccompound (3a). On the other hand, the reaction of 1a with 2-propynylamine (2c) gave exclusivelythe bicyclic compound (5c). In the reactions with the secondary 2-propynylamines (2d,e), thetetracyclic compounds (3d,e) were exclusively formed. The reactions of 1a with α-branched primary1,1-dialkyl-2-propynylamines (2f,g) gave mixtures of 3- and 5-type compounds. The tetracycliccompounds 3 were formed from the intramolecular [4+2]π cycloadditions of the [1,5]-sigmatropicrearrangement products of the 1,4 adducts of 1a and 2, followed by the [1,5]-sigmatropicrearrangement of hydrogen and dehydrogenation. The bicyclic compounds 5 were derived from the[2π+2π+2σ] reaction of the 1,4 adducts of 1a and 2. The one-pot multistage sequential pericyclicreactions were discussed on the basis of the X-ray crystallographic structures and the MO calculationdata.
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