Abstract
The FeCl3-mediated reaction of alkynols with iodine resulted in intramolecular addition of hydroxyl to alkyne to produce a wide range of iodocycloenol ethers in good to excellent yields under mild reaction conditions. On the other hand, 1,2-diiodides were obtained in good yields when propargyl alcohol reacted with iodine in the same condition.
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ACKNOWLEDGMENTS
The authors are grateful to the NSF of China (20772099) and Natural Science Foundation of Jiangxi Province (2009GZH00013) for financial support.
Notes
a Reactions were conducted with catalyst (0.3 mmol), 5-hexyn-1-ol (1.0 mmol), and iodine (1.0 mmol) in CH3CN (5 mL) at rt.
b Isolated yield.
c Reaction was conducted with 5-hexyn-1-ol (1.0 mmol) and iodine (1.5 mmol) in CH3CN (5 mL) at rt.
d (E)-2a was isolated as a single diastereomerm, and the E-conformer was confirmed by NOESY experiment.
e 0.2 mol equiv FeCl3 · 6H2O was used.
f 1.0 mol equiv FeCl3 · 6H2O and 0.5 mol equiv I2 were used.
a All reactions were conducted with FeCl3 · 6H2O (1.0 mmol), alkynol (1.0 mmol), and iodine (0.5 mmol) in CH3CN (5 mL) at rt.
b Isolated yield.
c Not detected and 4-phenyl pent-3-en-1-yne was obtained with 15% yield because the reaction was messy.
d 2b was isolated as a single diastereomer and was expected to be E-conformer by the reaction mechanism (Scheme 2).
e Ratio determined by 1H NMR analysis.