Access to β‐Ketonitriles through Nickel‐Catalyzed Carbonylative Coupling of α‐Bromonitriles with Alkylzinc Reagents
作者:Aske S. Donslund、Karoline T. Neumann、Nicklas P. Corneliussen、Ebbe K. Grove、Domenique Herbstritt、Kim Daasbjerg、Troels Skrydstrup
DOI:10.1002/chem.201902206
日期:2019.7.25
Herein, we report a nickel‐catalyzed carbonylative coupling of α‐bromonitriles and alkylzinc reagents with near stoichiometric carbon monoxide to give β‐ketonitriles in good yields. The reaction is catalyzed by a readily available and stable nickel(II) pincercomplex. The developed protocol tolerates substrates bearing a variety of functional groups, which would be problematic or incompatible with
Asymmetric Synthesis of a New Salen Type-titanium Complex as the Catalyst for Asymmetric Trimethylsilylcyanation of Aldehydes
作者:Zheng-Chang Lin、Chinpiao Chen
DOI:10.1002/jccs.201000101
日期:2010.8
This work describes the asymmetric synthesis of a new salen‐type ligand via a Diels‐Alder reaction and Curtius rearrangement. The ligand with a norbornane skeleton was used in the trimethylsilylcyanation of aldehydes, but the enantioselectivity was 55%ee. The norborane skeleton was cleaved to destroy this rigidity, and the eanatioselectivity was thereby increased to 85%ee.
A removable functional group strategy for regiodivergent Wittig rearrangement products
作者:Md Nirshad Alam、Lakshmi K. M.、Pradip Maity
DOI:10.1039/c8ob02221f
日期:——
[1,2] and [2,3] Wittig rearrangements are competing reaction pathways, often leading to uncontrollable product distribution. We employ a single removable functional group to fulfill the dual role of attaining a reversible [2,3] and stabilizing radical intermediate for the [1,2] path to obtain both the Wittig products selectively for a broad range of substrates.
N-silyl oxyketene imines are underused yet highly versatile reagents for catalytic asymmetric synthesis
作者:Scott E. Denmark、Tyler W. Wilson
DOI:10.1038/nchem.857
日期:2010.11
process, arguably the most characteristic reaction of d1 synthetic equivalents, finds no general solution for reactions involving aliphatic acyl anions. In this Article, we introduce a new class of stable, isolable silyl ketene imines derivedfrom protected cyanohydrins. These nucleophiles serve as acyl anion equivalents in Lewis base catalysed aldol addition reactions and allow for the preparation of cross-benzoin
Ester Synthesis in Water: <i>Mycobacterium smegmatis</i>
Acyl Transferase for Kinetic Resolutions
作者:Nicolas de Leeuw、Guzman Torrelo、Carolin Bisterfeld、Verena Resch、Luuk Mestrom、Emanuele Straulino、Laura van der Weel、Ulf Hanefeld
DOI:10.1002/adsc.201701282
日期:2018.1.17
The acyl transferase from Mycobacterium smegmatis (MsAcT) catalyses transesterification reactions in aqueous media because of itshydrophobic active site. Aliphatic cyanohydrin and alkyne esters can be synthesised in water with excellent and strikingly opposite enantioselectivity [(R);E>37 and (S);E>100, respectively]. When using this enzyme, the undesired hydrolysis of the acyl donor is an important