Interrupted carbonyl-olefin metathesis via oxygen atom transfer
作者:Jacob R. Ludwig、Rebecca B. Watson、Daniel J. Nasrallah、Joseph B. Gianino、Paul M. Zimmerman、Ren A. Wiscons、Corinna S. Schindler
DOI:10.1126/science.aar8238
日期:2018.9.28
from established acid-catalyzed carbonyl-ene, Prins, and carbonyl-olefin metathesis reaction paths. A range of epsilon, zeta-unsaturated ketones undergo Brønsted acid–catalyzed intramolecular cyclization to provide tetrahydrofluorene products via the formation of two new carbon-carbon bonds. Theoretical calculations and accompanying mechanistic studies suggest that this carbocyclization reaction proceeds
A palladium catalyst system has been developed that allows for the direct acylation of aryl chlorides with aldehydes. The choice of ligand, as well as the presence of pyrrolidine and molecular sieves is shown to be critical to the catalysis, which appears to proceed via an enamine intermediate. The reaction was successful for a wide range of aryl chlorides and tolerant of functionality on the aldehyde component, giving easy access to alkyl aryl ketones in modest to good yields.
作者:Tuong Anh To、Chao Pei、Rene M. Koenigs、Thanh Vinh Nguyen
DOI:10.1002/anie.202117366
日期:2022.3.21
H-bonding network: Hexafluoroisopropanol (HFIP) can act as a hydrogen-bond donor to enhance the catalytic efficiency of simple Brønsted acid catalysts in carbonyl-olefin metathesis reactions by stabilization of all transition states and intermediates along the reaction pathway.