Reactions with Cyclic Transitions States

2-Benzisoxazole and alicyclic ketones undergo a mercury sulfate-catalyzed cycloaddition in boiling xylene. The enol tautomers (141) are apparently involved and the yields of 

Although l,2-benzisoxazol-2-ines are known, their chemistry has received little attention to date 81AHC(29)1, p. 29). 

Photolysis in general produced oxazoles and a variety of other products including aminochalcones, nitriles, aldehydes and chalcone oximes. A number of photolytic intermediates have been postulated, represented by (151), (152), (153) and (154) (77CL1195, 75T1373, 73HCA2588, 73TL2283). 

A number of manipulations on isoxazolinone can be performed with the nucleus remaining intact, and a variety of reagents cleave the ring. Isoxazolin-5-ones have also been used as synthons for the production of other heterocycles (76ZC270). 

The treatment of ethyl Af-methyl-5-oxo isoxazoline-4-carboxylate with NaOH generated ethyl Af-methylmonomalonamide. The reaction in the case of 3-unsubstituted derivatives 

The distinction between Diels-Alder reactions and 1,3-dipolar cycloadditions is semantic for the five-membered rings Diels-Alder reaction at the F/B positions in (357) (four atom fragment) is 

An intramolecular [4 + 2] cycloaddition is represented by a thermal conversion of allylphenoxy- and allyloxyphenoxy-pyridazines into xanthenes (80CPB198). 

Pyridazinium and phthalazinium dicyanomethylides give indolizines as primary adducts with 1,2,3-triphenylcyclopropene, either by [4 + 2] cycloaddition or by 1,3-dipolar addition of the ylide to triphenylcyclopropene (81JCS(P1)73). 

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REACTIONS WITH CYCLIC TRANSITION STATES 5.02.9.1 Cycloadditions... 

Reactions involving radicals, reducing agents and at surfaces Reactions with cyclic transition states Reactions of substituents Other reactions... 

D. Reactions with Cyclic Transition States 1. Cycloadditions to N-Oxides... 

Reactions with Cyclic Transition States, Formally Involving a Second Species 433... 

E. Reactions with Cyclic Transition states 1. Six-Membered Rings Diels-Alder Reactions... 

Reactions with Cyclic Transition States 3.2.1.10.1 Introduction... 

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