4747-11-9Relevant articles and documents
Iodine catalysed synthesis of unsymmetrical benzylic ethers by direct cross-coupling of alcohols
Kharrngi, Balamphrang,Basumatary, Grace,Bez, Ghanashyam
supporting information, (2021/09/13)
Although symmetrical ethers can be synthesized easily from alcohols, synthesis of unsymmetrical ethers by dehydrative cross-coupling of alcohols is still a challenge. While dehydrative cross-coupling is environmentally appealing due to formation of water as the only byproduct, the chances for formation of symmetrical ethers always exist. The existing transition metal based methods give good selectivity, but the catalyst are costly and not readily available. Here, we present a simple, readily available, and cost-effective catalyst in the form of molecular iodine which catalyzes a highly selective cross-coupling of benzylic alcohols with benzyl, alkyl, and aryl alcohols to give their corresponding unsymmetrical ethers in good to excellent yield.
α-Lithiobenzyloxy as a Directed Metalation Group in ortho-Lithiation Reactions
Sedano, Carlos,Velasco, Rocío,Feberero, Claudia,Suárez-Pantiga, Samuel,Sanz, Roberto
supporting information, p. 6365 - 6369 (2020/08/24)
The α-lithiobenzyloxy group, easily generated from aryl benzyl ethers by selective α-lithiation with t-BuLi at low temperature, behaves as a directed metalation group (DMG) providing a direct access to o-lithiophenyl α-lithiobenzyl ethers. This ortho-directing effect is reinforced in substrates bearing an additional methoxy group at the meta position. The generated dianions can be reacted with a selection of electrophiles including carboxylic esters and dihalosilanes or germanes, which afford interesting benzofuran, sila(germa)dihydrobenzofuran, and silachroman derivatives from simple aryl benzyl ethers.
Exploring the Reactivity of α-Lithiated Aryl Benzyl Ethers: Inhibition of the [1,2]-Wittig Rearrangement and the Mechanistic Proposal Revisited
Velasco, Rocío,Silva López, Carlos,Nieto Faza, Olalla,Sanz, Roberto
supporting information, p. 15058 - 15068 (2016/10/11)
By carefully controlling the reaction temperature, treatment of aryl benzyl ethers with tBuLi selectively leads to α-lithiation, generating stable organolithiums that can be directly trapped with a variety of selected electrophiles, before they can undergo the expected [1,2]-Wittig rearrangement. This rearrangement has been deeply studied, both experimentally and computationally, with aryl α-lithiated benzyl ethers bearing different substituents at the aryl ring. The obtained results support the competence of a concerted anionic intramolecular addition/elimination sequence and a radical dissociation/recombination sequence for explaining the tendency of migration for aryl groups. The more favored rearrangements are found for substrates with electron-poor aryl groups that favor the anionic pathway.
