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We disclose a reaction cascade involving cyclopropylimine rearrangement and the Povarov reaction for the synthesis of hexahydropyrroloquinolines from anilines and cyclopropyl aldehydes. This method provides facile and convenient access to pharmacologically significant pyrrolo[3,2-c]quinoline derivatives which are not easily accessible using the existing methods. [ABSTRACT FROM AUTHOR]

The addition of an alkynyl cyclopropyl mechanistic probe to a digermyne did not lead to any ring-opened rearrangement products indicating that the reaction pathway does not involve any vinylic radicals or cations and providing experimental insight into the addition of alkynes to digermynes. [ABSTRACT FROM AUTHOR]

Reactions of anhydrous lanthanide trichlorides, LnCl3 (Ln = Nd, Sm, Ho), with 3 equiv. of lithium-cyclopropylethinylamidinates, Li[c-C3H5–C≡C–C(NR)2] (1a: R = cyclohexyl (Cy), 1b: R = iPr), afforded the new homoleptic lanthanide(iii) tris(cyclopropylethinylamidinate) complexes [c-C3H5–C≡C–C(NCy)2]3Sm (2a) and [c-C3H5–C≡C–C(NiPr)2]3Ln (Ln = Nd (2b), Sm (2c), Ho (2d)) as air- and moisture-sensitive crystalline solids in moderate to good isolated yields (45–79%). The formation of unsolvated, homoleptic Ln(iii) tris(cyclopropylethinylamidinate) was confirmed by an X-ray diffraction study of the holmium derivative [c-C3H5–C≡C–C(NiPr)2]3Ho (2d). EI mass spectra of the new rare-earth metal amidinates indicated a significant volatility. An initial catalysis study revealed that these complexes catalyze the addition of terminal alkynes to carbodiimides to give propiolamidines of the type R–C≡C–C(=NR′)(NHR′). The molecular structure of N,N′-dicyclohexyl-phenylpropiolamidine, Ph–C≡C–C(NCy)(NHCy) (4), was also determined by X-ray diffraction. [ABSTRACT FROM AUTHOR]

An efficient AgOTf catalyzed tandem intramolecular transannulation of ((2-alkynyl)aryl)cyclopropyl ketones leading to the 2,3-dihydronaphtho[1,2-b]furans has been developed. The reaction features a regioselective alkyne hydration, cyclopropylketone-2,3-dyhydrofuran rearrangement, and benzannulation. The methodology gives direct access to the tricyclic core structure of biologically important 2,3-dihydronaphtho[1,2-b]furan natural products. [ABSTRACT FROM AUTHOR]

A regioselective synthesis of oxepinones and azepinones in good to excellent yields from alkynylcyclopropanecarboxylic acid derivatives is described. This novel cycloisomerization cascade process consists of a nucleophilic addition followed by a cyclopropane ring-opening, where both donor and acceptor groups are required as substituents of the cyclopropane ring. [ABSTRACT FROM AUTHOR]

The tandem Pauson–Khand type reactions of 1,4-enynes tethered by a cyclopropyl group with two molecules of CO proceed smoothly in the presence of [Rh(CO)2Cl]2 under a CO atmosphere to give the corresponding 6-hydroxy-2,3-dihydro-1H-inden-1-one derivatives in moderate yields under mild conditions. [ABSTRACT FROM AUTHOR]

A Fe-catalytic highly selective ring expansion reaction of alkynylcyclopropyl alkanols to alkynylcyclobutanols via a 1,2-carbon shift under mild conditions was developed. A new class of homogeneous FeCl2/O2 catalytic system was employed in these novel transformations. [ABSTRACT FROM AUTHOR]