Asymmetric Allylation/Pauson-Khand Reaction: A Simple Entry to Polycyclic Amines. Application to the Synthesis of Aminosteroid Analogues

Asymmetric allylation of o-iodoarylsulfinylimines has been achieved in high diastereoselectivities. The thus-obtained o-iodoarylhomoallylic sulfinamides participate in a subsequent Sonogashira coupling followed by a diastereoselective intramolecular Pauson-Khand reaction. In this way, tricyclic amines showing a unique benzo-fused indenyl backbone were obtained. The methodology has been applied to the synthesis of amino steroid analogues.

Synthesis and application of β-substituted Pauson-Khand adducts: trifluoromethyl as a removable steering group.

The reaction between alkynes (I) and norbornadiene (II) affords the β-substituted Pauson—Khand adducts (III) as single regioisomers and the trifluoromethyl steering group can be easily removed in the presence of DBU and water.

Innentitelbild: Synthesis and Application of β-Substituted Pauson-Khand Adducts: Trifluoromethyl as a Removable Steering Group (Angew. Chem. 20/2013)

Inside Cover: Synthesis and Application of β-Substituted Pauson-Khand Adducts: Trifluoromethyl as a Removable Steering Group (Angew. Chem. Int. Ed. 20/2013)

ChemInform Abstract: Asymmetric Allylation/Pauson-Khand Reaction: A Simple Entry to Polycyclic Amines. Application to the Synthesis of Aminosteroid Analogues.

Asymmetric allylation of o-iodoarylsulfinylimines has been achieved in high diastereoselectivities. The thus-obtained o-iodoarylhomoallylic sulfinamides participate in a subsequent Sonogashira coupling followed by a diastereoselective intramolecular Pauson–Khand reaction. In this way, tricyclic amines showing a unique benzo-fused indenyl backbone were obtained. The methodology has been applied to the synthesis of amino steroid analogues.

Pauson-Khand reaction of internal dissymmetric trifluoromethyl alkynes. Influence of the alkene on the regioselectivity.

Abstract: The scope of the Pauson-Khand reaction (PKR) of internal trifluoromethyl alkynes, previously described with norbornadiene, is expanded to norbornene and ethylene. A thorough structural analysis of the resulting PK adducts has been carried out to unveil that α-trifluoromethylcyclopentenones are preferred in all cases, independently of the electronic properties of the alkyne. The regioselectivity observed with norbornadiene and ethylene is higher than in the case of norbornene.

CCDC 989965: Experimental Crystal Structure Determination

Related Article: Santos Fustero, Rubén Lázaro, Nuria Aiguabella, Antoni Riera, Antonio Simón-Fuentes, and Pablo Barrio|2014|Org.Lett.|16|1224|doi:10.1021/ol500142c

CCDC 927146: Experimental Crystal Structure Determination

Related Article: Nuria Aiguabella, Carlos del Pozo, Xavier Verdaguer, Santos Fustero, Antoni Riera|2013|Angew.Chem.,Int.Ed.|52|5355|doi:10.1002/anie.201300907