Tungsten-, Molybdenum-, and Cerium-Promoted Regioselective and Stereospecific Halogenation of 2,3-Epoxy Alcohols and 2,3-Epoxy Sulfonamides
摘要:
The first catalytic regioselective and stereospecific halogenation of 2,3-epoxy alcohols and 2,3-epoxy sulfonamides has been developed. Under the catalysis of commercially available W- or Mo-salts, complemented by the method using cerium halides, the C-3 selective ring opening of structurally diverse epoxides with Cl-, Br-, and I-nucleophiles afforded various halohydrins in good yields and high regioselectivities.
substrates in asymmetric epoxidation reactions. In this study, chiral primary amines are shown to catalyze the asymmetric epoxidation of α-substitutedacroleins, a versatile type of 1,1-disubstituted terminal alkene. Among various chiral primary amines explored, the chiral primary-tertiary vicinal diamine derived from trans-1,2-diphenylethane-1,2-diamine is identified as the optimal catalyst, which, in combination
Tungsten-Catalyzed Regio- and Enantioselective Aminolysis of<i>trans</i>-2,3-Epoxy Alcohols: An Entry to Virtually Enantiopure Amino Alcohols
作者:Chuan Wang、Hisashi Yamamoto
DOI:10.1002/anie.201408732
日期:2014.12.8
The first catalytic enantioselectiveaminolysis of trans‐2,3‐epoxy alcohols has been accomplished. This stereospecific ring‐opening process was efficiently promoted by a tungsten/bis(hydroxamic acid) catalytic system, furnishing various anti‐3‐amino‐1,2‐diols with excellent regiocontrol and high enantioselectivities (up to 95 % ee). Moreover, virtually enantiopure 3‐amino‐1,2‐diols could be obtained
Ligand-Free Nickel-Catalyzed Reductive Allylic Defluorinative Cross-Coupling of α-Trifluoromethyl Alkenes with Epoxides
作者:Chuan Wang、Zhiyang Lin、Yun Lan
DOI:10.1055/s-0040-1707170
日期:2021.9
We report a reductive allylic defluorinative reaction of α-trifluoromethyl alkenes with terminal epoxides, which consists of an iodide-mediated regioselective ring opening and a nickel-catalyzed radical-type cross-coupling, providing diverse tertiary gem-difluorobishomoallylic alcohols in moderate to high yields. Notably, this reaction is conducted under mild conditions and requires no external ligand
Borinic Acid Catalyzed, Regioselective Chloroacylations and Chlorosulfonylations of 2,3-Epoxy Alcohols
作者:Kashif Tanveer、Kareem Jarrah、Mark S. Taylor
DOI:10.1021/acs.orglett.5b01541
日期:2015.7.17
In the presence of a borinic acid derived catalyst, 2,3-epoxy alcohols undergo couplings with acyl and sulfonyl chlorides. This transformation directly generates O-acylated or O-sulfonylated chlorohydrin diols, with significant levels of regioselectivity for both the ring-opening and O-functionalization steps.
Enzymic resolution of 2-substituted oxiranemethanols, a class of synthetically useful building blocks, bearing a chiral quaternary center