Wichterle reaction
The Wichterle reaction is a name reaction in organic chemistry, which was first introduced in 1948 by the Czech chemist Otto Wichterle (1913–1998) and named after him.
Overview reaction
This reaction is a modification of the Robinson annulation in which 1,3-dichloro-2-butene- 2 is used as the equivalent to methyl vinyl ketone to avoid undesirable condensation and polymerization during the Michael addition step. Similarly, 1,3-dichloro-2-butene is also referred to as Wichterle reagent. In this reaction, the cyclohexanone derivative 1 is fused to the product 3 shown by means of 1,3-dichloro-2-butene 2 .
Reaction mechanism
It is assumed that the cyclohexanone derivative 1 is first converted to an alcoholate 2 by treatment with lithium diisopropylamide (LDA) . The substituted γ-chlorocrotyl 3 is then treated with sulfuric acid to remove the chlorine. In order to then initiate the annealing, an additional LDA is added 4 . The lithium 5 can then be removed by adding water and it is released as lithium hydroxide (LiOH). The remaining hydroxyl group combines with a hydrogen atom 6 , which means that it can come off as water and the desired product 7 is formed.
application
This reaction is widely used in the production of condensed cyclic compounds.
Individual evidence
- ↑ Zerong Wang: Wichterle Reaction . In: Comprehensive Organic Name Reactions and Reagents . John Wiley & Sons, Inc., Hoboken, NJ, USA 2010, ISBN 978-0-470-63885-9 , doi : 10.1002 / 9780470638859.conrr669 ( wiley.com [accessed March 7, 2019]).
- ↑ Miloš Hudlický: The Wichterle Reaction . In: Collection of Czechoslovak Chemical Communications . tape 58 , no. 10 , 1993, p. 2229–2244 , doi : 10.1135 / cccc19932229 ( cas.cz [accessed March 7, 2019]).