Nickel/Photo-Cocatalyzed Asymmetric Acyl-Carbamoylation of Alkenes
作者:Pei Fan、Yun Lan、Chang Zhang、Chuan Wang
DOI:10.1021/jacs.9b12554
日期:2020.2.5
of pendant alkenes tethered on aryl carbamic chlorides with both aliphatic and aromatic aldehydes has been developed via the cooperative catalysis of a chiral nickel-PHOX complex and tetrabutylammonium deca-tungstate. This reaction represents the first example of merging hydrogen-atom-transfer photochemistry and asymmetric transition metal catalysis in difunctionalization of alkenes. Using this protocol
aldehydes and α-trifluoromethyl alkenes, which provides novel and efficientaccess to diverse gem-difluorohomoallylic alcohols. Remarkably, the high chemoselectivity of this reaction enables the conversion of the formyl moiety in the presence of various easily reducible functionalities including ketone, organohalides, aziridine, sulfone, alkyne, and unactivated alkene. The utility of this method is demonstrated
作者:David S. Laitar、John W. Kramer、Bryan T. Whiting、Emil B. Lobkovsky、Geoffrey W. Coates
DOI:10.1039/b913698c
日期:——
4-Substituted oxazolines, which are readily synthesized from naturally occurring α-amino acids, are converted efficiently and stereospecifically to β-amidoaldehydes in the presence of synthesis gas and catalytic dicobalt octacarbonyl.
The tandem Michael-SN2 reaction for the construction of the 3-azabicyclo[3.1.0]hexane ring system
作者:Samantha Chan、Tamim F. Braish
DOI:10.1016/s0040-4020(01)89609-5
日期:1994.1
The 3-azabicyclo[3.1.0]-hexane ringsystem was constructed in a convergent one-pot procedure starting from readily available starting materials, using the intramolecular tandem Michael-SN2 reaction. The methodology was also extended to the synthesis of 3-azabicyclo[4.1.0]heptane ringsystem.
In the present study, Fmoc-β-Ala-H was immobilized to a serine-modified ChemMatrix resin and used for the automated assembly of two peptidealdehydes and one aldehyde-modified peptide nucleic acid (PNA). In addition, a triantennary N-acetyl-d-galactosamine-cluster with a β-Ala-H unit has been synthesized. These aldehydes were conjugated via N-(methoxy)oxazolidine-linkage to therapeutically relevant