A Formal Synthesis of (-)-Perhydrohistrionicotoxin Using a Cross Metathesis-Hydrogenation Approach.

The development of an efficient, high yielding six-step convergent synthesis of the semisynthetic alkaloid (-)-perhydrohistrionicotoxin is described. The key transformations include the cross metathesis of a Brønsted-acid masked primary homoallylic amine with a vinyl cyclohexenone and a regioselective palladium catalyzed hydrogenation. This sequence generated the advanced Winterfeldt spirocyclic precursor in 47% overall yield, with a longest linear sequence of five steps.

Cross-Metathesis of Brønsted Acid Masked Alkenylamines with Acrylates for the Synthesis of Polyamide Monomers.

Ruthenium-alkylidene-catalyzed cross-metathesis of a range of homologous alkenylamine salts provides expedient and high-yielding routes to commercially valuable polyamide monomers using a single catalyst, telescopic workup, and mild experimental conditions.

Tandem Ru-alkylidene-catalysed cross metathesis/hydrogenation: synthesis of lipophilic amino acids.

Highly efficient synthesis of lipidic amino acids can be achieved via Ru-alkylidene-catalysed cross metathesis of long chain alkenes with commercially available allylglycine. The resultant unsaturated analogues can be then optionally hydrogenated under mild reaction conditions by using the spent metathesis catalyst.

Lanthanoid-based ionic liquids incorporating the dicyanonitrosomethanide anion.

A series of low-melting-point salts with hexakisdicyanonitrosomethanidolanthanoidate anions has been synthesised and characterised: (C(2) mim)(3) [Ln(dcnm)(6)] (1 Ln; 1 Ln=1 La, 1 Ce, 1 Pr, 1 Nd), (C(2) C(1) mim)(3) [Pr(dcnm)(6)] (2 Pr), (C(4) C(1) pyr)(3) [Ce(dcnm)(6)] (3 Ce), (N(1114))(3) [Ln(dcnm)(6)] (4 Ln; 4 Ln=4 La, 4 Ce, 4 Pr, 4 Nd, 4 Sm, 4 Gd), and (N(1112OH) )(3) [Ce(dcnm)(6)] (5 Ce) (C(2) mim=1-ethyl-3-methylimidazolium, C(2) C(1) mim=1-ethyl-2,3-dimethylimidazolium, C(4) C(1) py=N-butyl-4-methylpyridinium, N(1114) =butyltrimethylammonium, N(1112OH) =2-(hydroxyethyl)trimethylammonium=choline). X-ray crystallography was used to determine the structures of complexes 1 La, 2 Pr, and 5 Ce, all of which contain [Ln(dcnm)(6)](3-) ions. Complexes 1 Ln and 2 Pr were all ionic liquids (ILs), with complex 3 Ce melting at 38.

A simple amine protection strategy for olefin metathesis reactions.

Acyclic diamines are valuable feedstocks for polyamide synthesis. Ruthenium-alkylidene catalysed cross metathesis of amino alkenes is problematic and acyl derivatisation can result in less efficient syntheses, poor catalyst turnover and isomerisation. Temporary amine masking via stable and soluble ammonium salts delivers cyclic and acyclic aminoalkenes in high yield and purity.