Radical induced disproportionation of alcohols assisted by iodide under acidic conditions

Abstract

The disproportionation of alcohols without additional reductant and oxidant to simultaneously form alkanes and aldehydes/ketones represents an atom-economic transformation, which has great potential for organic synthesis. However, only limited methodologies...

Iodine and Iodide in Reductive Transformations

“…The addition of different amounts of water led to an increase in the yield of 5‐MF (Scheme 16a) [39] . Under optimized conditions, 5‐MF and DFF were obtained in a 49 % yield each by using NaI and sulfuric acid (H 2 SO 4 ) in tetrahydrofuran (THF) under N 2 atmosphere at 180 °C [44] . The application of the NaI/H 2 SO 4 deoxygenation process to a small collection of alcohols showed that substituents had no significant effect on the yields and ratios of disproportionation products (Scheme 16b).…”

“…[43] In addition to Yang's research on iodide-mediated processing of biomass derivatives to added-value chemicals, a disproportionation of alcohols catalyzed by iodide was also described. [44] Previously, Yang found that when 5-hydroxymeth- ylfurfural was exposed to NaI, a Brønsted acid, and H 2 under anhydrous conditions, it generated 5-methylfurfural (5-MF) and diformylfurfural (DFF). The addition of different amounts of water led to an increase in the yield of 5-MF (Scheme 16a).…”

“…[39] Under optimized conditions, 5-MF and DFF were obtained in a 49 % yield each by using NaI and sulfuric acid (H 2 SO 4 ) in tetrahydrofuran (THF) under N 2 atmosphere at 180 °C. [44] The application of the NaI/H 2 SO 4 deoxygenation process to a small collection of alcohols showed that substituents had no significant effect on the yields and ratios of disproportionation products (Scheme 16b). Methyl carbinols led to both elimination and disproportionation products, while allylic substrates reacted predictably.…”

Photocatalyst‐free Light‐driven Dehydrogenation of Alcohols into Carbonyl Compounds under Mild Conditions

“…As a result, apart from the desired product benzaldehyde (4 a) was generated, benzoic acid (5 a) was also presented as an accompanied product with the yields of 41%, which was detrimental to the selectivity of reaction (Table 2, Entry 1). Inspired by the previous studies on selective dehydrogenation of primary alcohols, [13] various iodides were used as additives to suppress the formation of 5 a.…”

“…The one pathway was direct cleavage of the OÀ H bond via transition state TS 12 and TS 33 with the generation of the product 2 a and 4 a, the energy barriers for such process was calculated as 44.23 and 43.26 kcal/ mol, respectively. The other pathway was that the 1,3-H shift process was first occurred within the intermediate 1 a-OOH (formed by combination of 1 a * and HOO * ) and 3 a-OO À (formed ), thereafter the final product 2 a and 4 a was produced by the cleavage of CÀ O bond within the intermediate via transition state TS 13 and TS 34 . The calculation showed that the energy barrier of the 1,3-H shift process within the intermediate 1 a-OOH and 3 a-OO À were 1.63 and 4.48 kcal/ mol, respectively, besides, the cleavage of CÀ O bond was proved to be an energy barrierless process by relax scanning calculation, which indicated that the latter pathway was more preferable for the reaction of 1 a * and 3 a * .…”