A facile and versatile Pd/L8-catalyzed asymmetric [3+2] cycloaddition of 3-diazooxindoles with a new vinylcyclopropane to construct spiropyrazolidine derivatives has been developed.

A novel palladium-catalyzed oxidative cyclization of aniline-tethered alkylidenecyclopropanes using molecular oxygen as the terminal oxidant through β-carbon elimination of aminopalladation intermediates is disclosed. The reaction opens up an effective way to obtain a series of 2- and 3-vinylindoles which are important synthetic intermediates in many natural indole derivatives.

Metal-free and environmentally friendly synthesis highly controlled by natural sources like visible light and air (or oxygen) is always a pursuit of green chemistry. In this paper, an atmosphere and light tuned highly diastereoselective synthesis of two important polyheterocyclic skeletons: cyclobuta/penta[b]indoles from aniline-tethered alkylidenecyclopropanes with alkynes, has been developed. The chiral cyclobuta/penta[b]indoles have also been obtained by optical resolution.

Controlled stepwise reaction of a geminal substituted alkene or primary amine group afforded a small library of new functionalised tertiary and ditertiary phosphines. Accordingly, Mannich based condensation of the commercially available disubstituted arene C 6 H 4 (NH 2){2-C(Me)=CH 2 } with HOCH 2 PR 2 (R 2 = Cg: 1,3,5,7-tetramethyl-2,4,8-trioxa-6phosphaadamantyl; Ph 2) afforded the (aminomethyl)phosphines C 6 H 4 (NHCH 2 PCg){2-C(Me)=CH 2 } L 1 and C 6 H 4 (NHCH 2 PPh 2){2-C(Me)=CH 2 } L 2 in approx. 60% yield. In addition to the formation of L 2 , the diphosphine L 3 was also identified and independently synthesised upon reaction of C 6 H 4 (NH 2){2-C(Me)=CH 2 } with two equiv. of HOCH 2 PPh 2 in CH 3 OH under reflux. Alternatively, reaction of C 6 H 4 (NH 2){2-C(Me)=CH 2 } with H-PR 2 (R 2 = Cg or Ph 2) in the presence of AIBN [2,2`-azobis(2-methylpropionitrile)] as free radical initiator, afforded the primary amine functionalised phosphines C 6 H 4 (NH 2){2-CH(Me)CH 2 PCg} L 4 and C 6 H 4 (NH 2){2-CH(Me)CH 2 PPh 2 } L 5 in 85% and 66% isolated yields respectively. In both cases only the anti-Markovnikov addition products were observed. Subsequent reaction of L 5 with HOCH 2 PR 2 (R 2 = Ph 2) afforded the unsymmetrical ditertiary phosphine C 6 H 4 (NHCH 2 PPh 2){2-CH(Me)CH 2 PPh 2 } L 6. Some preliminary coordination studies towards [RuCl(µ-Cl)(η 6-C 10 Η 14)] 2, [AuCl(tht)] (tht = tetrahydrothiophene) and [MCl 2 (η 4-cod)] (M = Pd, Pt; cod = cycloocta-1,5-diene) demonstrate these new ligands behave as classic P-donors leaving the pendant amino or alkenyl groups non-coordinating. All compounds have been characterised by multinuclear NMR, FT−IR, mass spectrometry and microanalysis. Single crystal X-ray studies have been performed on L 3 , L 5 , L 6 , 1, 3b•0.5CH 2 Cl 2 , 4a•1.5CH 2 Cl 2 , 5 and 6•0.5CDCl 3 •0.5C 4 H 10 O

A facile Pd-catalyzed intramolecular transfer hydrogenation and cycloaddition of p-quinamine-tethered alkylidenecyclopropanes has been developed, giving rigid tricyclic perhydroindole skeletons in moderate to good yields.