Halogenated catechols from cycloaddition reactions of η-(2-ethoxyvinylketene)iron(0) complexes with 1-haloalkynes.
1-chloroalkynes and 1-bromohexyne undergo cycloaddition reactions with ethoxyvinylketeneiron(0) complexes to form chloro and bromocatechols. With most substituents, the halogen is incorporated ortho to the phenolic hydroxyl group regioselectively. With chloroethyne, chlorohexyne, and methyl chloropropiolate, the reverse regioselection is observed. Ab initio calculations reveal that the products are, in most cases, nearly isoenergetic, which indicates that the intermediate ketene-alkyne adduct geometry must be important in determining the product distribution.
Truong
Jimmy
J
Long Island University, Department of Chemistry and Biochemistry, 1 University Plaza, Brooklyn, New York 11201, USA.
Caze
Vioela
V
Akhani
Ravish K
RK
Joshi
Gayatribahen K
GK
Kakalis
Lazaros
L
Matsunaga
Nikita
N
Schnatter
Wayne F K
WF