Science of Synthesis

Uyanik, M.; Ishihara, K., Science of Synthesis: Catalytic Oxidation in Organic Synthesis, (2017) 1, 654.

A highly efficient and general intra- and intermolecular oxidative α-C—O coupling (α-acyloxylation) reaction is catalyzed by in situ generated ammonium hypoiodite species with hydrogen peroxide or tert-butyl hydroperoxide as an environmentally benign oxidant.[‌67‌] Tetrabutylammonium iodide as the catalyst and hydrogen peroxide or tert-butyl hydroperoxide as an inexpensive and environmentally benign oxidant are used in place of iodobenzene and 3-chloroperoxybenzoic acid, respectively. In contrast to organoiodine-catalyzed reactions,[‌48‌] the highly chemoselective oxylactonization (intramolecular coupling) of 5-oxo- and 6-oxocarboxylic acids proceeds under milder conditions to give 5-acyltetrahydrofuran-2-ones (γ-acyl-γ-butyrolactones) ‌51‌ (n = 1) and 6-acyltetrahydropyran-2-ones ‌51‌ (n = 2), and water is the only byproduct derived from the oxidant (‌Scheme 18‌).[‌67‌] 5-Aroyl- and 5-hetaroyltetrahydrofuran-2-ones ‌51‌ (e.g., R1 = Ph, 2-FC6H4, 2-MeOC6H4, 2-pyridyl; n = 1) are obtained in excellent yields. No Baeyer–Villiger products are obtained. However, 5-alkanoyltetrahydrofuran-2-ones ‌51‌ (e.g., R1 = Me; n = 1) are obtained in only moderate yields; these derivatives are potent substrates for industrial use, and there is a strong demand for an efficient synthetic method for these compounds. The oxylactonization of aliphatic 5-oxocarboxylic acids under modified conditions gives the corresponding 5-acyltetrahydrofuran-2-ones in high yields, for example the formation of spirolactone ‌52‌ (‌Scheme 19‌).[‌68‌] The main inactivation path for the hypoiodite/hydrogen peroxide oxidation system may be the catalytic decomposition of hydrogen peroxide by the hypoiodite (or hypoiodous acid)/iodide couple. Dilute reaction conditions and slow addition of the oxidant are each highly effective for the promotion of this high-performance hypoiodite/hydrogen peroxide catalytic oxidation system.

‌Meeeee 88‌ Meeeeeeeee-Meeeeeeee Meeeeeeeeeeeeeee ee 8-Mee- eee 8-Meeeeeeeeeeee Meeee[‌88‌]

‌Meeeeeeeeee 88‌

e	M8	M8	Meeee (%)	Mee
8	Me	M	88	[‌88‌]
8	(MM8)8		88	[‌88‌]
8	Me	M	88	[‌88‌]
8	8-MM8M8	M	88	[‌88‌]
8	8-MeMM8M8	M	88	[‌88‌]
8	8-eeeeeee	M	88	[‌88‌]
8			88	[‌88‌]
8	Me	M	88	[‌88‌]

‌Meeeee 88‌ Meeeeeeeee-Meeeeeeee Meeeeeeeeeeeeeee ee 8-(8-Meeeeeeeeeeee)eeeeeeeee Meee eeeee Meeeeeee Meeeeeeeee[‌88‌]

Mee eee ee e eeeeeeeeee eeeeeeee ee eeee-eeeee eeeeeeeeeeeee ee eeeeeeeee eeeeee ee eeeeee ee eeeeeeee eeeeeeeeeeee (>88 °M) ee eeee eeeeeeeee eeee eeeeeee eeeeeeee eeeeeeee ee ee eeeeeee eee eee eeeeeeeeeeeeee eeeeeeeee eeeeeeee ee eeeeeee eeee eeeeeeeeee eeeee (‌Meeeee 88‌).[‌88‌] Mee eeeeeeeee eeeeeeee ee eeeeeee eeeeeeeeeeee eeeeeee eeeeeee, eeeeeeeee, eee 8,8-eeeeeeeeee eeeeeeeee eeee eeeeeeeeee eeeee eeeee eee eeeeeeeeeeeee α-eeeeeee eeeeeeee eeeeeeeee, e.e. ‌88‌ eee ‌88‌, ee eeee ee eeeeeeeee eeeeee. Meeeeeeeeee, eee eeeeeeee ee e eeeeeeeee eeeeee ee eeeeeeeeee eeeee eeeeee eeeeeeeeee (88 °M) ee eeeee ee ee eeeeeeeee eee eeeeeeeee eeeeeeeeeeeeeeee eee eee eeeeeeee ee eeeeeeeee. Mee eeeeeeee eeee eee ee eeeeeeeeeee eeeee eeeeee eeeeeeeeee eee ee eeeeeee eeeeeeeee ee eeeeeeeee eeee eeeeeeeeee. Meeeeee eeeeeeeeee eeeeee, eeee ee eeeeeeee ee eeeeeeee eeeeeeee, eeeeeeeee, eeeeee, eeeeee, eeeeeeee, eee eeeeee, eee eeeeeeeee eeeee eeeee eeeeeeeeee. Meeeeee, eeeeeeeeeeeee eeeeeee eee eeeeeeeeeee eeeee eee ee eeee ee eeeeeeee eeeeeeee ee eeee eee eeeeeeeeeeeee α-eeeeeeeeeee eeeeeee, eeeee eee eeee eeeeeeeeeeee ee eeeeeeee eeeeeeeee eee eee eeeeeeeeee ee eeeeeeeee eeeeeeee.

‌Meeeee 88‌ Meeeeeeeee-Meeeeeeee α-Meeeeeeeeeeee ee Meeeeee Meeeeeee Meeeeeeee eeee Meeeeeeeee Meeee[‌88‌]

‌Meeeeeeeeee 88‌

e 8 eee% ee eeeeeeeeee eee eeee.

‌Meeeeeeeeee 88M‌

e Meeeee (8 eeeee), eeeeeeeeee eeee (8 eeeee).

Mee α-eeeeeeeeeeeee ee eeeeeee ‌88‌ eeee eeeeee eeee ee eeee α-eeeeeee eeeeeee ‌88‌ eeee eeeeeeeeeeeeeeeeee eeeeeee ee eee eeeeeeee eee eeeeeee eeee-eeeee eeeeeeeeeeeee ee eee eeeeeee eeeee eeee-eeeeeeeeeee eeeeeeeeee (888 °M) (‌Meeeee 88‌).[‌88‌] Meeeeee, eeeee eeeeeeeeeeeeeeeeee eeeeeee ee eeeeeeeeeeeeeeeeee eeeeeeee ee eee eeeeeeeeeee, eeeeeee ee eeeeeeeeeeeeeeeeee eeeeee, eeeee eeeeee eeeeeeeeee ee eeeee eeeeeeeeeeee (88 °M) eee eee eeee eee eeeeeeee ee eee eeeee- ee eeeeeeeeeeeeee eeeeeeeee eeeeeeee eeeeeeee.[‌88‌]

‌Meeeee 88‌ α-Meeeeeeeeeeee ee Meeeeee Meeee Meeeeeeeeeeeeeeeee Meeeeee eee eeee-Meeee Meeeeeeeeeeee[‌88‌]

M eeeeeeeeeeeeeeeeee eeeeee eeeeeeeee eeee-eeeeeeeeeee eeeeeeeee ee α-eeeeeee eeeeeee ee eeeeeeee eeeee eeeeee eeeeeeeee ee eee eeeeeee eee eeeeeeee eeeeeee (‌Meeeee 88‌).[‌88‌] M eeeeeee ee 8-eeeeeee-8,8-eeeeeeeeeee-8-eeee ‌88‌ eee eeeeeeee ee eeee ee eeeeeeee eeeeee.

‌Meeeee 88‌ α-Meeeeeeeeeeee ee 8,8-Meeeeeeeeee-8-eeee eeee Meee Meeeeeee[‌88‌]

Meeeeee eeeeeeee eee ee eeeeeeee ee eee eeeeeeee eeeeeee eee eee eeeeeeeeeeeeeeeeee eeeeee eeeeeeeee α-eeeeeeeeeeeee ee eeeeeee ee eeee α-eeeeeee eeeeeee ‌88‌ (‌Meeeee 88‌).[‌88‌] Mee eeeeeeee ee eeeeeee ee eeeeeee eee eee eeeeeeee ee eeeeeee eeee e eeee-eeeee eeeeeeee eeee ee eeeeeeeee ee eeee eeee eee eeeeeeeee ee eeeeeeee ee eee eeeeeeee ee eeee-eeeee eeeeeeeeeeeee.

‌Meeeee 88‌ α-Meeeeeeeeeeee ee Meeeeee eeee Meeeeee Meeeeeee Meeee Meeeeeeeeeeeeeeeee Meeeee eee eeee-Meeee Meeeeeeeeeeee[‌88‌]

‌Meeeeeeeeee 88‌

e Meeeee (8 eeeee) eee eeee.

Meeeeeee eeeeeeeeeee eee eeee eeeeeeee ee ee eeeeeeeeeee eeeeeeeee eee eee eeeeeeeeeeeeeeeeee eeeeee eeeeeeeee α-eeeeeeeeeeeee ee eeeeeee ee eeee 8-eeeeeee-8-eeeeeeeee-8-eeee ‌88‌ (‌Meeeee 88‌).[‌88‌] Meeeeeee ee eeee eeeeee eee eeeeeeee eee e eeeeeee ee eeeeeeeeeeeeee eee eeeeeeeeeeee. Meeee eee eeeeeeeee eeeeeeeeee eeee eeee-eeeee eeeeeeeeeeeee ee eee eeeeeee, eeeeeeeeeee eee eeeeeeeee eeee eee eeeeeee eeeeeeee eeeeeeee, eeeeee, ee eeeeeeeeeee eeeee ee ee eeee eeee-eeeee eeeeeeee.

‌Meeeee 88‌ α-Meeeeeeeeeeeeee ee Meeeeee eeee Meeeeeee Meeeeeeeeee[‌88‌]

Meeeeeeeeeee Meeeeeeee

8-Meeeeeee[8.8]eeeeee-8,8-eeeee (‌88‌); Meeeeee Meeeeeeee:[‌88‌]

Me e eeeeeee eeeeeee ee 8-(8-eeeeeeeeeeeee)eeeeeeeee eeee (8.888 e, 8.88 eeee, 8.8 eeeee) eee MMMM (8.8888 e, 8.888 eeee, 8 eee%) ee MeMMe (888 eM) eee eeeee 88 ee% ee M8M8 (8.888 e, 8.88 eeee, 8.8 eeeee) ee eee eeeeeee ee 88 °M. Mee eeeeeeeee eeeeeee eee eeeeee ee 88 °M. Meeee eeeee eeeeeee eee 8 e, eee eeeeeee eee eeeeee ee ee eee eeeeee eeee e eeeeeee ee eee. ee Me8M8M8 (88 eM) eee eee. ee MeMMM8 (88 eM). Mee eeeeeee eeeee eee eeeeeeeee eee eeeeeeeee eeee MeMMe (8 ×). Mee eeeeeeee eeeeeee eeeeee eeee eeeeee eeee eeeee eee eeeee (Me8MM8). Mee eeeeeee eee eeeeeee eeeee eeeeeee eeeeeeee eee eee eeeeeee eee eeeeeeee ee eeeeeeeeeeeeee (eeeeee eee, eeeeee/MeMMe 8:8); eeeee: 8.888 e (88%).

α-Meeeeeeeeeeeeeee ‌88‌; Meeeeee Meeeeeeee:[‌88‌]

Me e eeeeeee eeeeeee ee eeeeeeee (8.8 eeee, 8.8 eeeee), eeeeeeeeee eeee (8.8 eeee, 8.8 eeeee), eeeeeeeeee (8.88 µM, 8.88 eeee, 8 eee%), eee MMMM (88.8 ee, 8.8 eeee, 88 eee%) ee MeMMe (8.8 eM) eee eeeee 8.8 M e-MeMMM ee eeeeee ee eeeeee (888 µM, 8.8 eeee) ee ee. Mee eeeeeeeee eeeeeee eee eeeeee ee 88 °M. Meeee eee eeeeeeee eee eeeeeeee, eee eeeeeee eee eeeeee ee ee eee eeeeee eeee Me8M8M8 (8 eM) eee MeMMM8 (8 eM). Mee eeeeeee eeeee eee eeeeeeeee eee eeeeeeeee eeee MeMMe (8 ×). Mee eeeeeeee eeeeeee eeeeee eeee eeeeee eeee eeeee eee eeeee (Me8MM8). Mee eeeeeee eee eeeeeee eeeee eeeeeee eeeeeeee eee eee eeeeeee eee eeeeeeee ee eeeeeeeeeeeeee (eeeeee eee, eeeeee/MeMMe).

α-Meeeeee Meeeeee ‌88‌; Meeeeee Meeeeeeee:[‌88‌]

Me e eeeeeee eeeeeee ee eeeeee (8.8 eeee, 8.8 eeeee), eeeeeeeeee eeee (8.8 eeee, 8.8 eeeee), eee MMMM (88.8 ee, 8.8 eeee, 88 eee%) ee MeMMe (8.8 eM) eee eeeee 8.8 M e-MeMMM ee eeeeee ee eeeeee (888 µM, 8 eeee) ee ee. Mee eeeeeeeee eeeeeee eee eeeeee ee 88 °M. Meeee eee eeeeeeee eee eeeeeeee, eee eeeeeee eee eeeeee ee ee eee eeeeee eeee Me8M8M8 (8 eM) eee MeMMM8 (8 eM). Mee eeeeeee eeeee eee eeeeeeeee eee eeeeeeeee eeee MeMMe (8 ×). Mee eeeeeeee eeeeeee eeeeee eeee eeeeee eeee eeeee eee eeeee (Me8MM8). Mee eeeeeee eee eeeeeee eeeee eeeeeee eeeeeeee eee eee eeeeeee eee eeeeeeee ee eeeeeeeeeeeeee (eeeeee eee, eeeeee/MeMMe).

References