Beilstein J. Org. Chem.2019,15, 2747–2752, doi:10.3762/bjoc.15.265
of the α-iodo intermediate, and methodology studies demonstrate that alkyl-capped, asymmetric, internal alkynes undergo a regiospecific hydration, also via the 5-exo-dig NGP pathway.
Keywords: α-iodo intermediate; internal alkyne; iodine-mediatedhydration; neighboring group participation
(II) [7], silver(I) [8], and gold(I)/(III) [9][10][11][12]. While less toxic than mercury, such catalysts are still environmental hazards and tend to be costlier [13][14]. The iodine-mediatedhydration described herein is a viable solution to these issues [15][16]. This metal-free method produces
room temperature.
Previous work by our group has shown that terminal alkynes on keto scaffolds undergo iodine-mediatedhydration to form 1,4-diketo products 2 (Scheme 1) [15]. At that time, our studies revealed that a keto group must be present in the substrate, as the hydration requires neighboring
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Graphical Abstract
Scheme 1:
Proposed mechanism for the iodine-mediated hydration of terminal alkynes 1 [15].