Nuclear Magnetic Resonance Studies of Boron Trifluoride Addition Compounds. III. Rates and Mechanism for the Exchange of Boron Trifluoride between Ethyl Ether—Boron Trifluoride and Tetrahydrofuran—Boron Trifluoride and between Ethyl Ether—Boron Trifluoride and Ethyl Sulfide—Boron Trifluoride1

1965 ◽  
Vol 69 (2) ◽  
pp. 527-531 ◽  
Author(s):  
A. C. Rutenberg ◽  
A. A. Palko
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Ethyl Ether ◽  
Boron Trifluoride ◽  
Magnetic Resonance Studies ◽  
Nuclear Magnetic

Nuclear magnetic resonance studies of ketone•BF3 complexes. II. The boron trifluoride catalyzed condensation of acetone

1968 ◽  
Vol 46 (24) ◽  
pp. 3799-3811 ◽  
Author(s):  
R. J. Gillespie ◽  
J. S. Hartman
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Boron Trifluoride ◽  
Methylene Chloride ◽  
Aldol Condensation ◽  
Condensation Reaction ◽  
Magnetic Resonance Studies ◽  
Exchange Processes ◽  
Donor Acceptor ◽  
Nuclear Magnetic

A detailed study of the reactions of the acetone•BF3 complex in excess acetone has been carried out by "F nuclear magnetic resonance (n.m.r.) spectroscopy. It is shown that rapid reversible fluorine exchange processes occur in solution, in addition to the slower aldol condensation–dehydration reaction. Two of the new 19F absorptions which appear during the reaction are shown to arise from BF3 complexes of donors which are formed by condensation and dehydration of acetone. The rate of the aldol condensation reaction is shown to fall off markedly as an increasing proportion of the BF3 becomes complexed with water; thus BF3 catalysis of the reaction appears to depend on the existence of a ketone–BF3 donor–acceptor bond. 1H and 19F n.m.r. studies of the acetone•BF3 complex in methylene chloride throw some light on the apparent greatly decreased reactivity of the complex in this solvent. Evidence is presented for the reversibility of the first step of the condensation reaction.

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