Trifluoromethylthiolation and Trifluoromethylselenolation of α-Diazo Esters Catalyzed by Copper
作者:Christian Matheis、Thilo Krause、Valentina Bragoni、Lukas J. Goossen
DOI:10.1002/chem.201602730
日期:2016.8.22
α‐Diazo esters are smoothly converted into the corresponding trifluoromethyl thio‐ or selenoethers by reaction with Me4NSCF3 or Me4NSeCF3, respectively, in the presence of catalytic amounts of copper thiocyanate. This straightforward method gives high yields under neutral conditions at room temperature and is applicable to a wide range of functionalized molecules, including diverse α‐amino acid derivatives
A Catalytic Asymmetric Ring‐Expansion Reaction of Isatins and α‐Alkyl‐α‐Diazoesters: Highly Efficient Synthesis of Functionalized 2‐Quinolone Derivatives
Asymmetricexpansion: A catalyticasymmetricring‐expansionreaction of the title compounds occurs in the presence of a Sc(OTf)3 catalyst bearing an N,N′‐dioxide‐based ligand. Highlyfunctionalized2‐quinolonederivatives containing a chiral C4‐quaternary stereocenter were obtained in high yields and high levels of selectivity under mild reaction conditions (see scheme; Tf=trifluoromethanesulfonyl)
Enantioselective Synthesis of Cyclobutanes via Sequential Rh-catalyzed Bicyclobutanation/Cu-catalyzed Homoconjugate Addition
作者:Robert Panish、Srinivasa R. Chintala、David T. Boruta、Yinzhi Fang、Michael T. Taylor、Joseph M. Fox
DOI:10.1021/ja403811t
日期:2013.6.26
Enantiomerically enriched cyclobutanes are constructed by a three-component process in which t-butyl (E)-2-diazo-5-arylpent-4-enoates are treated with Rh2(S-NTTL)(4) to provide enantiomerically enriched bicyclobutanes, which can subsequently engage in homoconjugate addition/enolate trapping sequence to give densely functionalized cyclobutanes with high diastereoselectivity. This three-component, two-catalyst procedure can be carried out in a single flask. Rh-2(S-NTTL)(4)-catalyzed reaction of t-butyl (Z)-2-diazo-5-phenylpent-4-enoate gives the Buchner cyclization product in excellent enantioselectivity.