Asymmetric Total Synthesis and Stereochemical Elucidation of the Antitumor Agent PM-94128

Electroreductive Hydroxymethylation of Imines with Ketones To Access β-Amino Alcohols

In this article, an electrochemical method for the direct synthesis of β-amino alcohols from imines and ketones is described. Mechanistic studies, including a radical trapping experiment, electron paramagnetic resonance, cyclic voltammetry, and divided-cell electrolysis experiment, support the radical-involved reductive cross coupling of imines with ketones at the cathode. The use of abundant and easily prepared starting materials, high atom- and step-economy, and insensitivity to air and moisture make this synthetic strategy more efficient for the construction of various β-amino alcohol derivatives.

Application of Pd-Catalyzed C-H Alkylation Reaction in Total Syntheses of Twelve Amicoumacin-Type Natural Products

Enantioselective total syntheses of 12 amicoumacin-type natural products are accomplished with a palladium(II)-catalyzed C-H alkylation as the key step to furnish the 3,4-dihydroisocoumarin scaffold. The target chemicals are assembled in a convergent protocol by merging 3,4-dihydroisocoumarin derived amine part with categories of acid segments that are efficiently prepared by chemoselective catalytic oxidation of chiral 1,2-dihydroxyethylfuran-2(5H)-ones. Afterward, the cytotoxicity of amicoumacins on five cancer cell lines and one normal cell line is investigated.

A nickel-mediated oxidative α-C(sp3)–H functionalization of amides with allylic alcohols terminated by radical 1,2-aryl migration

A Ni-mediated oxidative C(sp³)–H functionalization of N,N-substituted amides with α,α-diaryl allylic alcohols through a radical 1,2-aryl migration process has been developed. This process features a broad substrate scope and excellent functional group tolerance.

An Expeditious Synthesis of [1,2]Isoxazolidin-5-ones and [1,2]Oxazin-6-ones from Functional Allyl Bromide Derivatives

Reaction of allyl bromide (Z)-1 and (Z)-2 with N-substituted hydroxylamine hydrochlorides in presence of tert-butoxide in tert-butanol at reflux provides a short and effective route to [1,2]isoxazolidin-5-ones 3 and [1,2]oxazin-6-ones 4.

Acetylides from alkyl propiolates as building blocks for C3 homologation

Alkyl propiolates are reagents with a versatile reactivity profile that entirely remains in the C(3)-homologated product for further elaboration. To be effective, this C(3) homologation requires suitable methods for the generation of the acetylide anion that are compatible with both the conjugated ester and the electrophilic partner. Recent advances include catalytic procedures for the in situ generation of these acetylides in the presence of suitable electrophiles. Whereas the organometallic methods have brought stereoselectivity to these reactions, the organocatalytic methods laid the ground for new efficient domino processes that generate complexity.

Stereoselective Synthesis of Novel β,γ-Epoxyhydroxylamines and 4-Hydroxyalkyl-1,2-oxazetidines

A simple and efficient stereoselective synthesis of polysubstituted beta,gamma-epoxyhydroxylamines and 4-hydroxyalkyl-1,2-oxazetidines, based on the addition of alpha-lithiated aryloxiranes to nitrones and subsequent cyclization of the corresponding intermediates in a 4-exo-tet mode, is described.

Marine natural products: synthetic aspects

An overview of marine natural products synthesis during 2003 is provided. The emphasis on total syntheses of molecules of contemporary interest, new total syntheses, and syntheses that have resulted in structure conformation or stereochemical assignments.

Diastereoselective Aldol Reaction of N,N-Dibenzyl-α-amino Aldehydes with Ketones Catalyzed by Proline

[reaction: see text] L-proline-catalyzed direct aldol reaction of L-amino acid-derived N,N-dibenzyl amino aldehydes with acetone, cyclopentanone, or hydroxyacetone provides gamma-amino-beta-hydroxy- or gamma-amino-alpha,beta-dihydroxy-ketones with moderate to excellent yields and diastereoselectivities.