ChemInform Abstract: Chirality Transfer in the 1,5-Hydride Shift of a Stannyl Compound Having Cationic Center at δ-Position.

ChemInform ◽  
1990 ◽  
Vol 21 (17) ◽  
Author(s):  
T. SATO ◽  
M. HARAMURA ◽  
N. TAKA
Keyword(s):  
Chirality Transfer ◽  
Hydride Shift

Chirality transfer in the 1,5-hydride shift of a stannyl compound having cationic center at δ-position

1989 ◽  
Vol 30 (37) ◽  
pp. 4983-4984 ◽  
Author(s):  
Tadashi Sato ◽  
Masayuki Haramura ◽  
Naoki Taka
Keyword(s):  
Chirality Transfer ◽  
Hydride Shift

Stereospecific 1,3-H Transfer of Indenols Proceeds via Persistent Ion-Pairs Anchored By NH···Pi Interactions

2018 ◽  
Author(s):  
David Ascough ◽  
Fernanda Duarte ◽  
Robert Paton
Keyword(s):  
Computational Analysis ◽  
Ion Pairs ◽  
Ion Pair ◽  
Hydrogen Atom Transfer ◽  
Polar Solvents ◽  
Chirality Transfer ◽  
Activation Barriers ◽  
Sense And Avoid ◽  
Phase Dynamics ◽  
Pi Interactions

The base-catalyzed rearrangement of arylindenols is a rare example of a suprafacial [1,3]-hydrogen atom transfer. The mechanism has been proposed to proceed via sequential [1,5]-sigmatropic shifts, which occur in a selective sense and avoid an achiral intermediate. A computational analysis using quantum chemistry casts serious doubt on these suggestions: these pathways have enormous activation barriers and in constrast to what is observed experimentally, they overwhelmingly favor a racemic product. Instead we propose that a suprafacial [1,3]-prototopic shift occurs in a two-step deprotonation/reprotonation sequence. This mechanism is favored by 15 kcal mol<sup>-1</sup> over that previously proposed. Most importantly, this is also consistent with stereospecificity since reprotonation occurs rapidly on the same p-face. We have used explicitly-solvated molecular dynamics studies to study the persistence and condensed-phase dynamics of the intermediate ion-pair formed in this reaction. Chirality transfer is the result of a particularly resilient contact ion-pair, held together by electrostatic attraction and a critical NH···p interaction which ensures that this species has an appreciable lifetime even in polar solvents such as DMSO and MeOH.

scholarly journals Regioselective activation of benzocyclobutenones and dienamides lead to anti-Bredt bridged-ring systems by a [4+4] cycloaddition

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jianyu Zhang ◽  
Xi Wang ◽  
Tao Xu
Keyword(s):  
Type Ii ◽  
Ring Systems ◽  
Hydride Shift

AbstractTo the best of our knowledge, bridgehead carbon benzofused-bridged ring systems have previously not been accessible to the synthetic community. Here, we describe a formal type-II [4 + 4] cycloaddition approach that provides fully sp2-carbon embedded anti-Bredt bicyclo[5.3.1] skeletons through the Rh-catalyzed C1–C8 activation of benzocyclobutenones (BCBs) and their coupling with pedant dienamides. Variously substituted dienamides have been coupled with BCBs to provide a range of complex bicyclo[5.3.1] scaffolds (>20 examples, up to 89% yield). The bridged rings were further converted to polyfused hydroquinoline-containing tetracycles via a serendipitously discovered transannular 1,5-hydride shift/Prins-like cyclization/Schmidt rearrangement cascade.

Chirality Transfer from a Chiral Primary Alcohol Equivalent Through Allyl Cyanate-to-Isocyanate Rearrangement: Synthesis of (+)-Geranyllinaloisocyanide

Synthesis ◽  
2019 ◽  
Vol 51 (15) ◽  
pp. 2959-2964 ◽  
Author(s):  
Yoshiyasu Ichikawa ◽  
Hirofumi Morimoto ◽  
Toshiya Masuda
Keyword(s):  
Natural Product ◽  
Primary Alcohol ◽  
Marine Natural Product ◽  
Chirality Transfer ◽  
New Approach ◽  
Stereogenic Centers ◽  
Quaternary Stereogenic Centers

A new approach was developed to construct quaternary stereogenic centers bearing nitrogen substituents in an enantioselective manner. The strategy takes advantage of [1,3]-chirality transfer from a chiral primary alcohol equivalent through an allyl cyanate-to-isocyanate rearrangement. This approach was employed in an efficient eight-step synthesis of the marine natural product, (+)-geranyllinaloisocyanide, in 43% overall yield.

A special-salt effect upon the hydride shift during the acetolysis of cyclohexyl tosylate

1976 ◽  
Vol 41 (24) ◽  
pp. 3920-3922 ◽  
Author(s):  
M. Gillard ◽  
F. Metras ◽  
S. Tellier ◽  
J. J. Dannenberg
Keyword(s):  
Salt Effect ◽  
Hydride Shift

Chirality Transfer in Magnetic Coordination Complexes Monitored by Vibrational and Electronic Circular Dichroism

ChemPlusChem ◽  
2014 ◽  
Vol 79 (5) ◽  
pp. 698-707 ◽  
Author(s):  
Tao Wu ◽  
Xiao-Peng Zhang ◽  
Xiao-Zeng You ◽  
Yi-Zhi Li ◽  
Petr Bouř
Keyword(s):  
Circular Dichroism ◽  
Coordination Complexes ◽  
Electronic Circular Dichroism ◽  
Chirality Transfer ◽  
Circular Dichroïsm
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