scholarly journals An Enantioconvergent Benzylic Hydroxylation Using a Chiral Aryl Iodide in a Dual Activation Mode

ACS Catalysis ◽  
2020 ◽  
Vol 10 (15) ◽  
pp. 8042-8048 ◽  
Author(s):  
Ayham H. Abazid ◽  
Nils Clamor ◽  
Boris J. Nachtsheim
2020 ◽  
Author(s):  
Ayham Abazid ◽  
Nils Clamor ◽  
Boris Nachtsheim

In this article we describe an enantioselective hydroxylation of benzylic C-H bonds with a unique activation mechanism. A chiral aryl iodide catalyst initially acts as precursor for a brominating reagent which subsequently brominates the benzylic C-H bond in a non-stereoselective fashion through a radical bromination. In the second step of this transofrmation, the same catalyst acts as a chiral ligand in a Cu-catalyzed enantioconvergent substitution. We present a broad substrate scope and an intial mechanistic proposal based on a plethora of control experiments.<br>


2020 ◽  
Author(s):  
Ayham Abazid ◽  
Nils Clamor ◽  
Boris Nachtsheim

In this article we describe an enantioselective hydroxylation of benzylic C-H bonds with a unique activation mechanism. A chiral aryl iodide catalyst initially acts as precursor for a brominating reagent which subsequently brominates the benzylic C-H bond in a non-stereoselective fashion through a radical bromination. In the second step of this transofrmation, the same catalyst acts as a chiral ligand in a Cu-catalyzed enantioconvergent substitution. We present a broad substrate scope and an intial mechanistic proposal based on a plethora of control experiments.<br>


2020 ◽  
Vol 7 (19) ◽  
pp. 2938-2943
Author(s):  
Yeojin Kim ◽  
Kwang Ho Song ◽  
Sunwoo Lee

Aryl sulfonyl hydrazide reacted with aryl iodide in the presence of CO to give the corresponding S-aryl thioesters.


ACS Nano ◽  
2021 ◽  
Author(s):  
Ziyin N. Huang ◽  
Cassandra E. Callmann ◽  
Lisa E. Cole ◽  
Shuya Wang ◽  
Chad A. Mirkin

2021 ◽  
Author(s):  
Hajime Kameo ◽  
Akihiro Mushiake ◽  
Tomohito Isasa ◽  
Hiroyuki Matsuzaka ◽  
Didier Bourissou

Pd/Ni → Ge–F interactions supported by phosphine-chelation were found to trigger dual activation of Ge–F bonds under mild conditions.


Languages ◽  
2021 ◽  
Vol 6 (3) ◽  
pp. 114
Author(s):  
Ulrich Reubold ◽  
Sanne Ditewig ◽  
Robert Mayr ◽  
Ineke Mennen

The present study sought to examine the effect of dual language activation on L1 speech in late English–Austrian German sequential bilinguals, and to identify relevant predictor variables. To this end, we compared the English speech patterns of adult migrants to Austria in a code-switched and monolingual condition alongside those of monolingual native speakers in England in a monolingual condition. In the code-switched materials, German words containing target segments known to trigger cross-linguistic interaction in the two languages (i.e., [v–w], [ʃt(ʁ)-st(ɹ)] and [l-ɫ]) were inserted into an English frame; monolingual materials comprised English words with the same segments. To examine whether the position of the German item affects L1 speech, the segments occurred either before the switch (“He wants a Wienerschnitzel”) or after (“I like Würstel with mustard”). Critical acoustic measures of these segments revealed no differences between the groups in the monolingual condition, but significant L2-induced shifts in the bilinguals’ L1 speech production in the code-switched condition for some sounds. These were found to occur both before and after a code-switch, and exhibited a fair amount of individual variation. Only the amount of L2 use was found to be a significant predictor variable for shift size in code-switched compared with monolingual utterances, and only for [w]. These results have important implications for the role of dual activation in the speech of late sequential bilinguals.


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