Dynamic Control of Chiral Space Through Local Symmetry Breaking in a Rotaxane Organocatalyst
作者:Marcel Dommaschk、Javier Echavarren、David A. Leigh、Vanesa Marcos、Thomas A. Singleton
DOI:10.1002/anie.201908330
日期:2019.10.14
We report on a switchable rotaxane molecular shuttle that features a pseudo-meso 2,5-disubstituted pyrrolidine catalytic unit on the axle whose localsymmetry is broken according to the position of a threaded benzylic amide macrocycle. The macrocycle can be selectively switched (with light in one direction; with catalytic acid in the other) with high fidelity between binding sites located to either
An effective dehydrochlorination of bis(phenylsulfonyl)alkane to prepare alkene building blocks is developed. The elimination together with double bond migration results in a variety of β,γ-unsaturated bis(phenylsulfonyl)olefins in good yields with only E geometry. The following chemical diversification represents an easy and straightforward access to a series of alkene building blocks.
Allylation of Carbon Pronucleophiles with Alkynes in the Presence of Palladium/Acetic Acid Catalyst
作者:Nitin T. Patil、Isao Kadota、Akinori Shibuya、Young Soo Gyoung、Yoshinori Yamamoto
DOI:10.1002/adsc.200404046
日期:2004.6
efficient and eco-chemical process for the allylation of carbon pronucleophiles with alkynes. The reaction of alkynes with various active methynes and methylenes in the presence of Pd(PPh3)4/acetic acid gave the corresponding allylated products in high yields and high regioselectivities. In the present catalytic system, the key is the use of carboxylic acid which dramatically enhances the rate of the
Synthesis of mono- and geminal dimetalated carbanions of bis(phenylsulfonyl)methane using alkali metal bases and structural comparisons with lithiated bis(phenylsulfonyl)imides
作者:Dugald J. MacDougall、Alan R. Kennedy、Bruce C. Noll、Kenneth W. Henderson
DOI:10.1039/b504730g
日期:——
The α,α′-stabilized carbanion complexes [(PhSO2)2CHLi·THF] 1, [(PhSO2)2CHNa·THF] 2 and [(PhSO2)2CHK] 3 were prepared by the direct deprotonation of bis(phenylsulfonyl)methane I in THF with one molar equivalent of MeLi, BuNa and BnK respectively. The geminal dianionic complexes [(PhSO2)2CLi2·THF] 4, [(PhSO2)2CNa2·0.55THF] 5 and [(PhSO2)2CK2] 6 were similarly prepared by the reaction of I with two molar
Catalytic Dehydrogenative (3 + 2) Cycloaddition of Alkylbenzenes via π-Coordination
作者:Wen-Qiang Wu、Yunzhi Lin、Yuntong Li、Hang Shi
DOI:10.1021/jacs.3c02900
日期:2023.5.3
long been of interest in organic synthesis. Herein we describe a method for rhodium-catalyzed dehydrogenative (3 + 2) cycloaddition reactions of alkylbenzenes with 1,1-bis(phenylsulfonyl)ethylene. The π-coordination with a rhodium catalyst facilitates the benzylic deprotonation, allowing for the subsequent (3 + 2) cycloaddition in which the metal-complexed carbanion serves as a unique all-carbon 1,3-dipole