Molecular modeling of the Wittig reaction. 3. A theoretical study of the Wittig olefination reaction: MNDO-PM3 treatment of the Wittig half-reaction of unstabilized ylides with aldehydes

1992 ◽  
Vol 114 (3) ◽  
pp. 813-821 ◽  
Author(s):  
Frank Mari ◽  
Paul M. Lahti ◽  
William E. McEwen
Keyword(s):  
Molecular Modeling ◽  
Wittig Reaction ◽  
Theoretical Study ◽  
Wittig Olefination

Theoretical study of the aza-Wittig reaction X3P=NH+O=CHCOOH→X3P=O+HN=CHCOOH for X=Cl, H and CH3

1999 ◽  
Vol 311 (6) ◽  
pp. 491-498 ◽  
Author(s):  
Wen Cai Lu ◽  
Chia Chung Sun ◽  
Qing Jun Zang ◽  
Cheng Bu Liu
Keyword(s):  
Wittig Reaction ◽  
Theoretical Study

scholarly journals Regioselectivity of glycosylation reactions of galactose acceptors: an experimental and theoretical study

2019 ◽  
Vol 15 ◽  
pp. 2982-2989 ◽  
Author(s):  
Enrique A Del Vigo ◽  
Carlos A Stortz ◽  
Carla Marino
Keyword(s):  
Molecular Modeling ◽  
Theoretical Study ◽  
General Trend ◽  
Relative Reactivity ◽  
Protecting Groups ◽  
Equatorial Orientation ◽  
Modeling Approach ◽  
Group A ◽  
The Difference ◽  
Glycosyl Donors

Regioselective glycosylations allow planning simpler strategies for the synthesis of oligosaccharides, and thus reducing the need of using protecting groups. With the idea of gaining further understanding of such regioselectivity, we analyzed the relative reactivity of the OH-3 and OH-4 groups of 2,6-diprotected methyl α- and β-galactopyranoside derivatives in glycosylation reactions. The glycosyl acceptors were efficiently prepared by simple methodologies, and glycosyl donors with different reactivities were assessed. High regioselectivities were achieved in favor of the 1→3 products due to the equatorial orientation of the OH-3 group. A molecular modeling approach endorsed this general trend of favoring O-3 substitution, although it showed some failures to explain subtler factors governing the difference in regioselectivity between some of the acceptors. However, the Galp-(β1→3)-Galp linkage could be regioselectively installed by using some of the acceptors assayed herein.

Theoretical study on the substituent effect of a Wittig reaction

2002 ◽  
Vol 107 (4) ◽  
pp. 206-210 ◽  
Author(s):  
W. C. Lu ◽  
N. B. Wong ◽  
R. Q. Zhang
Keyword(s):  
Substituent Effect ◽  
Wittig Reaction ◽  
Theoretical Study

scholarly journals A Wittig-olefination–Claisen-rearrangement approach to the 3-methylquinoline-4-carbaldehyde synthesis

2012 ◽  
Vol 8 ◽  
pp. 1725-1729 ◽  
Author(s):  
Mukund G Kulkarni ◽  
Mayur P Desai ◽  
Deekshaputra R Birhade ◽  
Yunus B Shaikh ◽  
Ajit N Dhatrak ◽  
...  
Keyword(s):  
Efficient Method ◽  
Wittig Reaction ◽  
Claisen Rearrangement ◽  
Aldehyde Group ◽  
Oxidative Cleavage ◽  
Reductive Cyclization ◽  
Vinyl Ethers ◽  
Terminal Olefin ◽  
Wittig Olefination ◽  
Step Procedure

Efficient syntheses are described for the synthetically important 3-methylquinoline-4-carbaldehydes 6a–h from o-nitrobenzaldehydes 1a–h employing a Wittig-olefination–Claisen-rearrangement protocol. The Wittig reaction of o-nitrobenzaldehydes with crotyloxymethylene triphenylphosphorane afforded crotyl vinyl ethers 2a–h, which on heating under reflux in xylene underwent Claisen rearrangement to give 4-pentenals 3a–h. Protection of the aldehyde group of the 4-pentenals as acetals 4a–h and subsequent oxidative cleavage of the terminal olefin furnished nitroaldehydes 5a–h. Reductive cyclization of these nitroaldehydes yielded the required 3-methylquinoline-4-carbaldehydes 6a–h in excellent yields. Therefore, an efficient method was developed for the preparation of 3-methylquinoline-4-carbaldehydes from o-nitrobenzaldehydes in a simple five-step procedure.

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