Stereoselection in nucleophilic substitution at an sp2 carbon

Miller, Sidney I.

doi:10.1016/0040-4020(77)80417-1

Cited by 42 publications

(4 citation statements)

References 70 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…72 Some cases of electrophilic addition to the double bond may also be regarded as X-philic reactions, and eq 16 could serve as an example.73,74 In many cases the solvent plays an important role in the reactions of the S^2X type.37,73,74,79 Thus, in the solution of bromotrinitromethane in dimethyl sulfoxide considerable C-Br separation takes place; this enables the trinitromethyl group to acquire the most planar configuration. 73 Another representative example of the double bond playing the role of a nucleophile is in the reaction of enamines with hexachloroacetone (eq 17).75 (17) The next candidates for the appropriate attacked group are cyano (eq 6)51-54,76-78 and nitro (eq 18)52,79,80 Z-+ 02N-C< -Z-N02 + -C< SnN02, AZ No2DNo2,c (18) groups. In these cases the atom attacked (carbon of CN and nitrogen of N02) carried a partial positive charge and reaction can be favored by this factor.…”

Section: Nucleophilesmentioning

confidence: 99%

X-philic reactions

Зефиров¹,

Makhon'kov²

1982

Chem. Rev.

201

View full text Add to dashboard Cite

Section: Nucleophilesmentioning

confidence: 99%

X-philic reactions

Зефиров¹,

Makhon'kov²

1982

Chem. Rev.

201

View full text Add to dashboard Cite

“…Nucleophilic substitution at saturated carbon remains one of the most important reactions in both synthetic and mechanistic organic chemistry. It is generally assumed that bimolecular S N 2 nucleophilic substitution at saturated carbon (sp 3 ) proceeds with inversion of configuration while S N 2 attack at vinylic carbon (sp 2 ) affords a substitution product with retention of configuration. , Reactions of nucleophilic vinylic substitution, however, display a greater variety of mechanisms. − Both the stepwise and the concerted processes normally lead to retention of configuration, although when the carbanion intermediate is long-lived, partial or complete stereoconvergence may result. − The most common reaction route is an addition−elimination mechanism (Ad N -E) that is initiated by nucleophilic attack at the π-bond 4-9 and portrays some features of aromatic nucleophilic substitution …”

Section: Introductionmentioning

confidence: 99%

Inversion versus Retention of Configuration for Nucleophilic Substitution at Vinylic Carbon

2001

View full text Add to dashboard Cite

A high-level computational study using CCSD, CCSD(T), and G2(+) levels of theory has shown that unactivated vinyl substrates such as vinyl chloride would afford gas phase, single-step halide exchange by a pure in-plane sigma-approach of the nucleophile to the backside of the C--Cl sigma bond. Geometry optimization by CCSD/6-31+G* and CCSD(T)/6-31+G* confirms the earlier findings of Glukhovtsev, Pross, and Radom that the S(N)2 reaction of Cl(-) with unactivated vinyl chloride in the gas phase occurs by a sigma attack. Complexation of vinyl chloride with Na(+) does not alter this in-plane sigma preference. However, moderately activated dihaloethylenes such as 1-chloro-1-fluoroethylene undergo gas-phase S(N)2 attack by the accepted pi-route where the nucleophile approaches perpendicular to the plane of the C==C. In the latter case a single-step pi pathway is preferred for the Cl(-) + H(2)C==CFCl reaction. This is the first definitive example at a high level of theory where a single-step pi nucleophilic vinylic substitution is preferred over a multistep mechanism in the gas phase. The activation barriers for these gas-phase single-step sigma- and pi-processes involving both naked anions and Na(+) complexes are, however, prohibitively high. Solvation and the presence of a counterion must play a dominant role in nucleophilic vinylic substitution reactions that proceed so readily in the condensed phase. In solution, nucleophilic vinylic substitution reactions involving electron-withdrawing groups on the carbon--carbon double bond (e.g., -CN, -CHO, and -NO(2)) would almost certainly proceed via a free discrete carbanionic intermediate in accord with experiment.

show abstract

“…Moreover, stereochemistry of the corresponding reactions was studied. Based on these results, the most probable mechanisms of the S N VIN reactions for the reactions of various halonitrostyrenes with nitrogen-, oxygen-, and sulfur-containing nucleophiles were suggested (9)(10)(11)(12)(13)(14)(15).…”

Section: Introductionmentioning

confidence: 99%

Nucleophilic reactions of ethylene derivatives. I. Reaction of α-iodo-β-nitrostyrene with sulfinic acids

Aleksiev

Ivanova

Valeva

2008

Journal of Sulfur Chemistry

View full text Add to dashboard Cite

1-Aryl-1-arylsulfonylethene derivatives have been prepared by the interaction of α-iodo-β-nitrostyrene with arenesulfinic acids. The structure of the products were confirmed by 1 H-NMR, IR, UV spectroscopy and elemental analysis. The kinetic studies indicated that the reaction took place via vinyl nucleophilic substitution mechanism. The principal kinetics and reaction parameters were determined.

show abstract

Stereoselection in nucleophilic substitution at an sp2 carbon

Cited by 42 publications

References 70 publications

X-philic reactions

X-philic reactions

Inversion versus Retention of Configuration for Nucleophilic Substitution at Vinylic Carbon

Nucleophilic reactions of ethylene derivatives. I. Reaction of α-iodo-β-nitrostyrene with sulfinic acids

Contact Info

Product

Resources

About