An unprecedented, tandem Aldol-Grob reaction sequence
- Univ. of Tennessee, Knoxville, TN (United States)
The authors report an unprecedented, tandem Aldol-Grob sequence involving the reaction of ketones with aromatic aldehydes in nonnucleophilic solvents in the presence of boron trifluoride. Although a detailed study of the reaction mechanism has not yet been completed, the consistent formation of (E)-alkene products, as well as the fact that aromatic aldehydes appear to be required, would point toward the intermediacy of a carbocation derivative. A reasonable mechanism would involve the formation of the mixed aldol followed by the formation and subsequent nonsynchronous ring opening of a lactol. The proposed fragmentation is reminiscent of two-step Grob fragmentations that have been reported for N-halo-{alpha}-amino acids and cyclobutane hemiacetals as well as the acid-catalyzed fragmentation of {beta}-hydroxy acetals. The authors examined the effect of various acids on the reaction sequence in order to ascertain which would be most efficient. They conclude that boron trifluoride is the most effective of the acids studied in achieving the new tandem condensation-cleavage sequence.
- OSTI ID:
- 659068
- Journal Information:
- Journal of Organic Chemistry, Journal Name: Journal of Organic Chemistry Journal Issue: 19 Vol. 63; ISSN 0022-3263; ISSN JOCEAH
- Country of Publication:
- United States
- Language:
- English
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