Network topology and cavity confinement-controlled diastereoselectivity in cyclopropanation reactions catalyzed by porphyrin-based MOFs
作者:Konstantin Epp、Bart Bueken、Benjamin J. Hofmann、Mirza Cokoja、Karina Hemmer、Dirk De Vos、Roland A. Fischer
DOI:10.1039/c9cy00893d
日期:——
that the stereoselectivity of a reaction can be controlled by directing groups of substrates, by network topology and by local cavity confinement of metal–organic framework (MOF) catalysts. We applied the porphyrin-based PCN-224(Rh), which contains no stereocenters in the cyclopropanation reaction using ethyl diazoacetate (EDA) as carbene source. When styrene and other non-coordinating olefins are used
Synthesis of 2,2‘-Bipyrroles and 2,2‘-Thienylpyrroles from Donor−Acceptor Cyclopropanes and 2-Cyanoheteroles
作者:Ming Yu、G. Dan Pantos、Jonathan L. Sessler、Brian L. Pagenkopf
DOI:10.1021/ol049857h
日期:2004.3.1
[reaction: see text] Two new series of 2,2'-bipyrroles and 2,2'-thienylpyrroles have been prepared by trimethylsilyl trifluoromethanesulfonate (TMSOTf)-mediated reaction of donor-acceptor cyclopropanes with 2-cyanopyrroles and 2-cyanothiophene, respectively. This method opens the door toward a wide variety of unsymmetrical bipyrroles and thienylpyrroles.
Synthesis of Indolizines and Benzoindolizines by Annulation of Donor-Acceptor Cyclopropanes with Electron-Deficient Pyridines and Quinolines
作者:Nicholas A. Morra、Christian L. Morales、Barbora Bajtos、Xin Wang、Hyosook Jang、Jian Wang、Ming Yu、Brian L. Pagenkopf
DOI:10.1002/adsc.200600298
日期:2006.11
The formal [3+2] dipolar cycloaddition (or annulation) of donor-acceptor cyclopropanoate esters with pyridines and 5-nitroquinoline is reported. Electron-deficientpyridine dipolarophiles (R=CN, CO2Et, COMe) participate in the annulation whereas electron rich species do not. The product 2,3-dihydroindolizines undergo rapid autooxidation, and the X-ray structures for two of the aromatic products are