199918-03-1Relevant articles and documents
A mild and efficient method for the selective cleavage of primary p-methoxybenzyl protecting group of saccharides by Co2(CO)8-Me2PhSiH-CO system
Qian, Peng-Zhan,Yao, Wang,Huang, Lu-Bai,Meng, Xiang-Bao,Li, Zhong-Jun
, p. 5238 - 5241 (2015)
A mild and efficient method to selectively cleave p-methoxybenzyl (PMB) ether with a catalytic amount of Co2(CO)8, hydrosilane and CO (1 atm) is presented. The cleavage reaction shows regioselectivity to primary O-PMB of a variety of
Stable Benzylic (1-Ethynylcyclohexanyl)carbonates Protect Hydroxyl Moieties by the Synergistic Action of [Au]/[Ag] Catalytic System
Chakraborty, Saptashwa,Mishra, Bijoyananda,Neralkar, Mahesh,Hotha, Srinivas
, p. 6604 - 6611 (2019/06/14)
Chemical syntheses of oligosaccharides and glycosides call utilization of many protecting groups that can be installed or deprotected without affecting other functional groups present. Benzyl ethers are routinely used in the synthesis of glycans as they can be subjected to hydrogenolysis under neutral conditions. However, installation of benzyl ethers is often carried out under strong basic conditions using benzyl halides. Many a times, strongly basic conditions will be detrimental for some of the other sensitive functionalities (e.g., esters). Later introduced reagents such as benzyl trichloroacetimidate and BnOTf are not shelf-stable, and hence, a new method is highly desirable. Taking a cue from the [Au]/[Ag]-catalyzed glycosidations, we have identified a method that enables protection of hydroxyl groups as benzyl, p-methoxybenzyl, or naphthylenemethyl ethers using easily accessible and stable carbonate reagent. A number of saccharide-derived alcohols were subjected to the benzylation successfully using a catalytic amount of gold phosphite and silver triflate. Furthermore, the protocol is suitable for even protecting menthol, cholesterol, serine, disaccharide OH, and furanosyl-derived alcohol easily. The often-utilized olefins and benzoates, as well as benzylidene-, silyl-, Troc-, and Fmoc-protecting groups do not get affected during the newly identified protocol. Regioselective protection and one-pot installation of benzyl and p-methoxybenzyl ethers are demonstrated.
Chiral and stereoselective total synthesis of novel immunosuppressant FR65814 from D-glucose
Amano, Seiji,Ogawa, Noriko,Ohtsuka, Masami,Chida, Noritaka
, p. 2205 - 2224 (2007/10/03)
The chiral synthesis of the immunosuppressive sesquiterpene, FR65814 1 is described. The cyclohexane ring in 1 was prepared in an optically active form from D-glucose using Ferrier's carbocyclization reaction, and the carbon side-chain in 1 was stereoselectively introduced via chirality transfer by way of Claisen rearrangement of the cyclohexenol derivative, followed by Pd- catalyzed Stille coupling. The bis-epoxide function was stereoselectively constructed by sulfur ylide chemistry and vanadium catalyzed epoxidation of a homoallyl alcohol derivative. This first total synthesis fully confirmed the proposed absolute structure of FR65814.
Substituted benzyl ethers as radical stable protecting groups
Liotta, Louis J.,Dombi, Kendra L.,Kelley, Sheryl A.,Targontsidis, Sonia,Morin, Amy M.
, p. 7833 - 7834 (2007/10/03)
Sixteen substituted benzyl ethers were studied for their potential to serve as hydroxyl protecting groups with the ability to withstand radical brominating conditions using N-bromosuccinimide during the conversion of benzylidene 2 into bromobenzoate 3.
Synthesis of a photoaffinity analogue of phosphatidylinositol 3,4-bisphosphate, an effector in the phosphoinositide 3-kinase signaling pathway
Thum, Oliver,Chen, Jian,Prestwich, Glenn D.
, p. 9017 - 9020 (2007/10/03)
A Ferrier rearrangement strategy starting from α-D-glucose gave a protected inositol, which after coupling to a chiral diacylglycerol phosphoramidite, provided a tritium-labeled, benzophenone-containing derivative of P-1-(O-aminopropyl) linked dipalmitoyl PtdIns(3,4)P2. Copyright (C) 1996 Elsevier Science Ltd.
