An official website of the United States government
Note: When clicking on a Digital Object Identifier (DOI) number, you will be taken to an external site maintained by the publisher.
Some full text articles may not yet be available without a charge during the embargo (administrative interval).
What is a DOI Number?
Some links on this page may take you to non-federal websites. Their policies may differ from this site.
-
A proline-squaraine ligand (Pro-SqEB) that demonstrates high levels of stereoselectivity in olefin cyclopropanations when anchored to a Rh2 II scaffold is introduced. High yields and enantioselectivities were achieved in the cyclopropanation of alkenes with diazo compounds in the presence of Rh2(Pro- SqEB)4. Notably, the unique electronic and steric design of this catalyst enabled the use of polar solvents that are otherwise incompatible with most RhII complexes.more » « less
-
Abstract This study describes an apparatus for high-precision variable temperature measurement of liquid vapor pressure. The apparatus can be used to measure the vapor pressure using only 0.5 ml of the liquid sample. To evaluate the accuracy of the device measurement, water and 2-propanol are utilized as standard liquids, and their vapor pressure is measured with a maximum uncertainty of ∼1%. This apparatus can be replicated using inexpensive and commonly used laboratory fittings and fixtures, making it an indispensable tool for synthetic chemists and chemical engineers involved in the iterative synthesis of compounds, targeting different vapor–liquid equilibrium regimes.more » « less
-
null (Ed.)Abstract (4+1)-Cyclizations are an underutilized disconnect for the formation of five-membered heterocyclic and carbocyclic frameworks. Herein we analyze methods employing oxyphosphonium enolates and RhII/PdII-metallocarbenes as C1 synthons in the presence of several four-atom components for the synthesis of 2,3-dihydrobenzofurans, 2,3-dihydroindoles, oxazolones, cyclopentenones, and pyrrolones. 1 Introduction 2 (4+1)-Cyclizations Employing Kukhtin–Ramirez-Like Reactivity 3 (4+1)-Cyclizations Employing a Cyclopropanation/Ring-Expansion Sequence 4 Pd-Catalyzed (4+1)-Cyclizations through Carbene Migratory Insertion/Reductive Elimination Processes 5 Summarymore » « less
