Step-Economical Access to Valuable Weinreb Amide 2,5-Disubstituted Pyrrolidines by a Sequential One-Pot Two-Directional Cross-Metathesis/Cyclizing Aza-Michael Process

Abstract

Double cross-metathesis of 1,5-hexadiene with a variety of electron-deficient alkenes including the reluctant Weinreb acrylamide has been successfully accomplished. It was found that the process is quite general, and microwave irradiation effectively accelerates cross-coupling metathesis. This promotes a very versatile and high yielding methodology for the synthesis of symmetric Michael acceptors, which can be transformed into 2,5-disubstituted pyrrolidines through a sequential one-pot two-directional cross-metathesis/ring-closing double aza-Michael process.

Modular Approach to Benzofurans, 2H‐Chromenes and Benzoxepines via Claisen Rearrangement and Ring‐Closing Metathesis: Access to Phenylpropanoids

“…Considering the easy access, to diallyl compound 27 prompted us to investigate whether the RCM is a feasible route to ring‐expanded analogues of the benzofuran. However, as depicted in previous literature, formation of benzoxepines by RCM [36b,c] might not be as facile as that of five‐ and six‐membered analogues. Occasionally, it impeded double bond isomerization and generally requires higher dilution [36d]…”

Synthesis of 2-aminosuberic acid derivatives as components of some histone deacetylase inhibiting cyclic tetrapeptides

“…To our delight, the reaction of 11 with anilide 13c proceeded well under our developed conditions and the CM product was obtained as a single isomer ( E -). Only a few successful reports on cross metathesis with Weinreb’s amide of acrylic acid, and N-alkylated acrylamides are known [ 30 – 33 ]. However, all attempts of CM reaction of 11 with the olefin 13d proved to be futile, a major problem being the inadequate solubility of the olefin in the reaction solvents tried, e.g., dichloromethane, dichloroethane, benzene, toluene etc.…”

Stereocontrolled synthesis of fluorine-containing functionalized β-lactam derivatives through cross-metathesis reactions

“…Two factors can contribute to the outcome of this reaction. First of all, chelation of the metallacycle intermediate with carbonyl oxygens is known to hinder further reactions by stabilizing the metallacycle [29][30][31]. During metathesis of the vinyl group attached directly to the lactam ring of (±)-11, formation of a 6-membered chelate ring with the oxo group of Boc is possible (Scheme 5, (±)-T2 (±)-T3).…”