- Palladium-Catalyzed Regio- A nd Enantioselective Hydrosulfonylation of 1,3-Dienes with Sulfinic Acids: Scope, Mechanism, and Origin of Selectivity
-
Chiral sulfones are important structural motifs in organic synthesis because of their widespread use in pharmaceutical chemistry. In particular, chiral allylic sulfones have drawn particular interest because of their synthetic utility. However, enantioselective synthesis of 1,3-disubstituted unsymmetrical chiral allylic sulfones remains a challenge. In this article, we report a protocol for (R)-DTBM-Segphos/Pd-catalyzed regio- A nd enantioselective hydrosulfonylation of 1,3-dienes with sulfinic acids, which provides atom- A nd step-economical access to 1,3-disubstituted chiral allylic sulfones. The reaction occurs under mild conditions and has a broad substrate scope. Combined experimental and computational studies suggest that the reaction is initiated by a ligand-to-ligand hydrogen transfer followed by a C-S bond reductive elimination via a six-membered transition state. Steric repulsion between the olefinic C-H of the substrate and the tert-butyl group of (R)-DTBM-Segphos was found to be a key factor in the enantiocontrol.
- Dong, Dongfang,Zhang, Qinglong,Zi, Weiwei
-
supporting information
p. 15860 - 15869
(2020/10/18)
-
- Soft propargylic deprotonation: Designed ligand enables au-catalyzed isomerization of alkynes to 1,3-Dienes
-
By functionalizing the privileged biphenyl-2-ylphosphine with a basic amino group at the rarely explored 3′ position, the derived gold(I) complex possesses orthogonally positioned "push" and "pull" forces, which enable for the first time soft propargylic deprotonation and permit the bridging of a difference of >26 pKa units (in DMSO) between a propargylic hydrogen and a protonated tertiary aniline. The application of this design led to efficient isomerization of alkynes into versatile 1,3-dienes with synthetically useful scope under mild reaction conditions.
- Wang, Zhixun,Wang, Yanzhao,Zhang, Liming
-
supporting information
p. 8887 - 8890
(2014/07/08)
-
- Stereoselective synthesis of 1,3-dienes from propargylic alcohols by LiAlH4/AlCl3
-
Herein we report that LiAlH4/AlCl3 is a very efficient reagent for the reductive dehydration of aryl propargylic alcohols in tetrahydrofuran solvent at reflux to give 1,3-dienes with good yields and high E selection. The reaction con
- Cui, Dong-Mei,Zhu, Kai,Chen, Li,Qi, Lang-Jun,Zhang, Cheng-Zhu,Zheng, Chen
-
supporting information
p. 2380 - 2384
(2013/07/26)
-
- A novel catalytic asymmetric route towards skipped dienes with a methyl-substituted central stereogenic carbon
-
A highly efficient method for the enantioselective synthesis of 1,4-dienes (skipped dienes) with a methyl-substituted central stereogenic carbon using copper-catalysed asymmetric allylic alkylation of diene bromides was developed. Excellent regio- and enantioselectivity (up to 97 : 3 SN2′/ SN2 ratio and 99% ee) were achieved with broad substrate scope. The Royal Society of Chemistry 2013.
- Huang, Yange,Fananas-Mastral, Martin,Minnaard, Adriaan J.,Feringa, Ben L.
-
p. 3309 - 3311
(2013/06/04)
-
- Rhodium-catalyzed isomerization of unactivated alkynes to 1,3-dienes
-
A rhodium/binap complex has been found to effectively catalyze the isomerization of unactivated internal alkynes to the corresponding 1,3-dienes in the presence of an azomethine imine as the reaction promoter. The Royal Society of Chemistry 2006.
- Shintani, Ryo,Duan, Wei-Liang,Park, Soyoung,Hayashi, Tamio
-
p. 3646 - 3647
(2008/09/20)
-
- 1,2- vs 1,4-Addition of acylbenzotriazoles to α,β-unsaturated aldehydes and ketones. A novel route to 3-alkyl-4,6-diaryl-3,4-dihydropyran-2-ones
-
Lithiation of aliphatic 1-acylbenzotriazoles with subsequent reaction with α,β-unsaturated ketones and aldehydes affords either 3,4,6-trisubstituted 3,4-dihydropyran-2-ones or 1,3-dienes depending on the carbonyl reagent used. Substituent effects on product yield and isomer ratio are discussed.
- Katritzky, Alan R.,Denisko, Olga V.
-
p. 3104 - 3108
(2007/10/03)
-
- Stereochemistry of direct olefin formation from carbonyl compounds and lithiated heterocyclic sulfones
-
The conditions for the title reaction were studied for the 2-benzothiazole and 2-pyridine series and for some examples in the 2-pyrimidine series.The olefin preparations were generally observed to be more efficient for 2-BT-sulfone systems.From the data of the hundred cases studied, it can be concluded that (E)-olefins are obtained: (i) from saturated BT-sulfones and aromatic aldehydes; and (ii) from benzylic BT-sulfones and branched saturated aldehydes (isobutyraldehyde, pivalaldehyde) or α,β-ethylenic or aromatic aldehydes. (Z)-olefins arise: (i) fom propargylic BT-sulfones and saturated or aromatic aldehydes; and (ii) from allylic or benzylic Pyr-sulfones and saturated aldehydes.Possible mechanisms for this new olefination procedure were examined. - heteroaromatic sulfones, organolithium derivatives, intramolecular ipso reactions, stereochemistry, elimination, olefination.
- Baudin, J. B.,Hareau, G.,Julia, S. A.,Lorne, R.,Ruel, O.
-
p. 856 - 878
(2007/10/02)
-
- Chemical process
-
Novel 2,4-dihydrocarbylspiro[5.5]undeca-1,4,8-trien-3-one compounds are prepared by reacting an N,N-dihydrocarbyl,2,6-dihydrocarbyl-4-aminomethylphenol with a conjugated diene and an alkyl halide in a liquid solvent medium.
- -
-
-