Tetramethylethylene diamine/trimethylsilyl chloride mediated addition of benzyl copper reagents to α,β-unsaturated esters

A succinct synthesis of the vaulted biaryl ligand vanol via a dienone-phenol rearrangement

Vanol is a member of the vaulted biaryl family of ligands and it has been proven to be very effective in a number of asymmetric catalytic reactions. The previous synthesis of vanol, while effective, is limited by the cost of reagents involved. The present work evaluates three different approaches to the synthesis of 3-phenyl-1-naphthol, a key intermediate in the synthesis of vanol. The first approach has its key step as the Michael addition of a benzyl Grignard to methyl cinnamate. In the second approach the key step is the first step, a Reformatsky reaction of ethyl bromoacetate and deoxybenzoin. The final and most-efficient approach involves a dienone-phenol rearrangement of a 4-aryl-1-tetralenone generated in-situ from the reaction of 4-chloro-1-naphthol with AlCl(3) and benzene, and preliminary results are reported on the extension of this method to substituted vanol derivatives.

Synthesis of HKI 0231B

[reaction: see text] The total synthesis of HKI 0231B (1b) was completed in 12 linear steps and 15.6% overall yield. An unusual anionic cyclization provided access to intermediate 61 and the embedded benz[cd]indol-3-(1H)-one ring system 3. Directed ortho-lithiation in the presence of a ketone followed by formylation and finally acid-catalyzed methanolysis complete the synthesis. Studies directed toward the construction and reactivity of the lactam acetal functionality present in HKI 0231A (1a) are also reported.

Synthesis and binding affinity of novel 3-aminoethyl-1-tetralones, potential atypical antipsychotics

A series of 3-aminoethyl-1-tetralones, conformationally constrained higher homologues of haloperidol (standard for typical antipsychotic profile), have been obtained by a four-step route from valerolactone. Their binding affinities at dopamine D(2) and serotonin 5-HT2A and 5-HT2C receptors were determined, showing in some cases an atypical antipsychotic profile.

1,6-Asymmetric induction during the conjugate addition of arylcopper reagents to a chiral sulfinyl-substituted pyrrolyl alpha,beta-unsaturated amide

The asymmetric conjugate addition of arylcopper reagents derived from aryl Grignard reagents and copper(I) iodide to a chiral 1-[2-(p-tolylsulfinyl)]pyrrolyl cinnamide proceeded smoothly to give (3R)-adducts with high diastereoselectivities (> or =92% de) in high yields. Conjugate additions either of the cinnamide with the alkyl Grignard reagent-copper(l) iodide combination or of the crotonamide derivative with aryl Grignard reagent-copper(l) iodide gave moderate to good diastereoselectivities. With these sulfinyl pyrrolyl alpha,beta-unsaturated amides, the chiral auxiliary was efficiently recovered without any loss of optical purity after asymmetric conjugate addition.

A versatile catalyst for Heck reactions of aryl chlorides and aryl bromides under mild conditions

In the presence of Cy2NMe, Pd/P(t-Bu)3 serves as an exceptionally mild and versatile catalyst for Heck reactions of aryl chlorides and bromides. A sterically and electronically diverse array of aryl bromides, as well as activated aryl chlorides, couple with a range of mono- and disubstituted olefins at room temperature, furnishing the arylated product with high E/Z stereoselection. The corresponding reactions of a broad spectrum of electron-neutral and electron-rich aryl chlorides proceed at elevated temperature, also with high selectivity. In terms of scope and mildness, Pd/P(t-Bu)3/Cy2NMe represents an advance over previously reported catalysts for these Heck coupling processes.

Constituents of the fungi Daedalea quercina and Daedaleopsis confragosa var. tricolor

Phytochemical examination of solvent extracts of the wood-rotting fungi Daedalea quercina and Daedaleopsis confragosa var. tricolor led to the isolation of five new triterpene derivatives and some known fungal constituents. All structures were identified by one- and two-dimensional NMR spectroscopy and mass spectrometry. From Daedalea quercina, the new natural products 16-O-acetylpolyporenic acid C, 16alpha-acetoxy-24-methylene-3-oxolanost-8-en-21-oic acid, (+)-24-methylene-3,23-dioxolanost-8-en-26-oic acid, (+)-3beta,12beta-dihydroxy-24-methyl-23-oxolanost-8-en-26-oi c acid and 12beta,23-epoxy-3alpha,23-dihydroxy-24-methyllanost-8- en-26-oic acid could be isolated. From Daedaleopsis confragosa var. tricolor, the compounds 3alpha-carboxyacetoxyquercinic acid, 3alpha-carboxyacetoxy-24-methylene-23-oxolanost-8-en-2 6-oic acid and 5alpha,8alpha-epidioxyergosta-6,22-dien-3beta-ol were identified. These are the first described triterpene derivatives isolated from this fungus.