Halogens displacement reactions

Pyran, 2-halotetrahydro-dipole moments, 3, 628 halogen displacement reactions, 2, 64 C NMR, 3, 587 Pyran, 2-hydroxy-synthesis, 3, 741 Pyran, 3-hydroxy-synthesis, 2, 91... 

A. Preparation.—Halogen displacement reactions have been used to prepare a number of new aminofluorophosphines. Aminodifluorophos-phine (1) has been prepared for the first time, from either bromodifluoro-phosphine or chlorodifluorophosphine, and ammonia. Studies of its n.m.r. spectrum have been made (see Chapter 11). The related NN-difluoroaminodifluorophosphine (2) has been prepared, from difluoroiodo-phosphine, and found to be explosive. Two syntheses of A-alkyl-amino-difluorophosphines have been reported, one of which was complicated by the subsequent formation of the phosphorane (3) and the bis-(A-alkylamino)fluorophosphine (4). 

Sn2 and SN2 Reactions with Halides and Sulfonates. Corey and Posner discovered that lithium dimethylcuprate can replace iodine or bromine by methyl in a wide variety of compounds, including aryl, alkenyl, and alkyl derivatives. This halogen displacement reaction is more general and gives higher yields than displacements with... 

These halogen displacement reactions may be carried out under PTC conditions, and have been reviewed.91... 

Halogen Displacement. Another activity series summarizes the halogens behavior in halogen displacement reactions ... 

The increase in for H displacement processes in Table 2.14b, relative to the halogen displacement reactions in Table 2.14a, is quite marked and a large fraction of the 3-5 kcal mole" of potential energy must be released as translational energy. Variations of Et for the F + C2H4 reaction also suggest that more than the statistical component of Ex is converted to... 

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