A computational study of the Hofmann elimination pathway for Morita–Baylis–Hillman reaction under DABCO catalysis: Participation of a bridge‐head ylide

2021 ◽  
Author(s):  
Veejendra K. Yadav
Keyword(s):  
Computational Study ◽  
Elimination Pathway ◽  
Hofmann Elimination

A Computational Study of the Hofmann Elimination Pathway for the MoritaBaylis-Hillman Reaction Under DABCO Catalysis. Participation of a Bridge-Head Ylide

2020 ◽  
Author(s):  
Veejendra Yadav
Keyword(s):  
Proton Transfer ◽  
Transition State ◽  
Computational Study ◽  
State Structure ◽  
Transition State Structure ◽  
Cyclic Transition ◽  
Activation Free Energy ◽  
Cyclic Transition State ◽  
Elimination Pathway ◽  
Hofmann Elimination

In comparison to the popular pathway involving proton-transfer via a four-centred cyclic transition state structure, the recently proposed overall lower energy pathway involving proton-transfer via a seven-centred cyclic transition state structure followed by Hofmann elimination for the Me<sub>3</sub>N-catalyzed Morita-Baylis-Hillman reaction is applicable to the DABCO-catalyzed reaction equally well. This finding clearly establishes that the zwitterion at the bridge-head in DABCO is well tolerated. Also, the activation free energy of the rate-limiting aldol reaction under DABCO-catalysis is lower than that under Me<sub>3</sub>N-catalysis, suggesting that DABCO is likely a better catalyst to achieve faster conversion.

A Computational Study of the Hofmann Elimination Pathway for the MoritaBaylis-Hillman Reaction Under DABCO Catalysis. Participation of a Bridge-Head Ylide

2020 ◽  
Author(s):  
Veejendra Yadav
Keyword(s):  
Proton Transfer ◽  
Transition State ◽  
Computational Study ◽  
State Structure ◽  
Transition State Structure ◽  
Cyclic Transition ◽  
Activation Free Energy ◽  
Cyclic Transition State ◽  
Elimination Pathway ◽  
Hofmann Elimination

In comparison to the popular pathway involving proton-transfer via a four-centred cyclic transition state structure, the recently proposed overall lower energy pathway involving proton-transfer via a seven-centred cyclic transition state structure followed by Hofmann elimination for the Me<sub>3</sub>N-catalyzed Morita-Baylis-Hillman reaction is applicable to the DABCO-catalyzed reaction equally well. This finding clearly establishes that the zwitterion at the bridge-head in DABCO is well tolerated. Also, the activation free energy of the rate-limiting aldol reaction under DABCO-catalysis is lower than that under Me<sub>3</sub>N-catalysis, suggesting that DABCO is likely a better catalyst to achieve faster conversion.

Stress transfer characteristics of sheathed strand in prestressed concrete beams: computational study

PCI Journal ◽  
2014 ◽  
Vol 59 (3) ◽  
pp. 95-109 ◽  
Author(s):  
Rigoberto Burgueño ◽  
Yi Sun
Keyword(s):  
Prestressed Concrete ◽  
Concrete Beams ◽  
Computational Study ◽  
Stress Transfer ◽  
Transfer Characteristics
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