Synthesis of highly enantio-enriched stereoisomers of hydroxy-GR24
作者:J. C. Morris、C. S. P. McErlean
DOI:10.1039/c5ob02349a
日期:——
In contrast to a biomimetic electrophilic cyclisation cascade, we employ a contra-biomimetic nucleophilic cyclisation cascade to give the tricyclic core of 4-hydroxy-GR24 in a single step. Kinetic resolution using a stereoselective Noyori transfer hydrogenation enables the concise synthesis of any enantiomerically enriched 4-hydroxy-GR24 stereoisomer.
作者:Christopher B. W. Phippen、James K. Beattie、Christopher S. P. McErlean
DOI:10.1039/c0cc02502j
日期:——
The conjugate addition of anilines onto unsaturated ketones, esters and N-acylpyrroles was investigated. Based on a recently proposed explanation for the phenomenon of on-water catalysis, operationally simple and mild reaction conditions for effecting these addition reactions have been developed. The success of these additions provides further support for the acid-catalysed nature of on-water chemistry.
作者:Alejandro Gómez-Palomino、Miquel Pellicena、Katrina Krämer、Pedro Romea、Fèlix Urpí、Gabriel Aullón、José M. Padrón
DOI:10.1039/c7ob00072c
日期:——
A total synthesis of (+)-herboxidiene/GEX 1A has been accomplished from (R)- and (S)-lactate esters in a highly efficient manner. Key steps of the synthesis involve substrate-controlled titanium-mediated aldol reactions from chiral lactate-derived ethyl ketones, an oxa-Michael cyclization, an Ireland–Claisen rearrangement, and a Suzuki coupling. Furthermore, computational studies of the oxa-Michael
Stetter Reactions of Unsaturated 1-Acyl-1H-pyrroles
作者:Christopher B. W. Phippen、Anna M. Goldys、Christopher S. P. McErlean
DOI:10.1002/ejoc.201101151
日期:2011.12
α,β-Unsaturated 1-acyl-1H-pyrroles are employed as enabling units for the construction of 1,4-dicarbonyl systems using the organocatalytic Stetterreaction. The enhanced electrophilicity of the 1-acyl-1H-pyrrole unit allows for the catalytic construction of fused and non-fused pyranones from aliphatic aldehydes, is compatible with aromatic aldehydes, and also facilitates an intermolecular variant of
Tandem catalysis in domino olefin cross-metathesis/intramolecular oxa-conjugate cyclization: concise synthesis of 2,6-cis-substituted tetrahydropyran derivatives
diastereoselectivity (“auto-tandem catalysis”). In addition, we have found that the domino CM/IOCC of δ-hydroxy olefins with α,β-unsaturatedcarbonylcompounds could be achieved simply by performing CM in the presence of a Brønsted acid in CH2Cl2 at 25–35 °C, which delivered 2,6-cis-substituted tetrahydropyrans in good yields with excellent diastereoselectivity (“orthogonal-tandem catalysis”). To understand the