Regioselectivity

Regioselectivity is a term from organic chemistry and describes a preferred reaction of or at certain points in a molecule . One of several potential reaction centers of an asymmetrically structured molecule reacts preferentially or exclusively regioselectively.

Examples

• Markovnikov's rule , e.g. B. the electrophilic addition of hydrogen bromide (HBr) to unsymmetrical alkenes
• Anti-Markovnikov rule , e.g. B. the radical addition of HBr to unsymmetrical alkenes
• Electrophilic substitution on monosubstituted aromatics in the ortho , meta and / or para position, relative to the first substituent
• Deprotonation of an unsymmetrical ketone
• 1,2-Elimination in the case of an unsymmetrical haloalkane , preferred formation of the Saytzeff product (more highly substituted alkene) instead of the Hofmann product (less substituted alkene).
• Selective substitution reaction on alkyl-substituted aromatics on the aromatic nucleus ( KKK rule ) or in the alkyl side chain ( SSS rule )
• Baldwin's rules for ring-closing reactions
• 1,2-addition of an organometallic compound to the carbonyl group of an α, β-unsaturated ketone or aldehyde
• 1,4-addition of an organometallic compound to an α, β-unsaturated ketone or aldehyde

Individual evidence

1. ↑ Otto-Albrecht Neumüller (Ed.): Römpps Chemie-Lexikon. Volume 5: Pl-S. 8th revised and expanded edition. Franckh'sche Verlagshandlung, Stuttgart 1987, ISBN 3-440-04515-3 , p. 3537.
2. ^ Ulrich Lüning: Organic reactions , 2nd edition, Elsevier GmbH, Munich, 2007, p. 72, ISBN 978-3-8274-1834-0 .
3. ^ Siegfried Hauptmann : Organic Chemistry , 2nd revised edition, VEB Deutscher Verlag für Grundstoffindindustrie, Leipzig, 1985, p. 234, ISBN 3-342-00280-8 .
4. ^ Ulrich Lüning: Organic reactions , 2nd edition, Elsevier GmbH, Munich, 2007, p. 75, ISBN 978-3-8274-1834-0 .
5. ↑ Ulrich Lüning: Organic reactions , 2nd edition, Elsevier GmbH, Munich, 2007, pp. 85–88, ISBN 978-3-8274-1834-0 .
6. ↑ Ulrich Lüning: Organic reactions , 2nd edition, Elsevier GmbH, Munich, 2007, pp. 116–117, ISBN 978-3-8274-1834-0 .
7. ^ Ulrich Lüning: Organic reactions , 2nd edition, Elsevier GmbH, Munich, 2007, pp. 58–59, ISBN 978-3-8274-1834-0 .