Heterograft copolymers of poly(ε‐caprolactone) prepared by combination of ATRA “grafting onto” and ATRP “grafting from” processes

This paper aims at reporting on the synthesis of a heterograft copolymer by combining the “grafting onto” process based on atom transfer radical addition (ATRA) and the “grafting from” process by atom transfer radical polymerization (ATRP). The statistical copolymerization of ε‐caprolactone (εCL) and α‐chloro‐ε‐caprolactone (αClεCL) was initiated by 2,2‐dibutyl‐2‐stanna‐1,3‐dioxepane (DSDOP), followed by ATRA of parts of the chlorinated units of poly(αClεCL‐co‐εCL) on the terminal double bond of α‐MeO,ω‐CH₂?CH? CH₂? CO₂‐poly(ethylene oxide) (PEO). The amphiphilic poly(εCL‐g‐EO) graft copolymer collected at this stage forms micelles as supported by dynamic light scattering (DLS) and transmission electron microscopy (TEM). The unreacted pendant chloro groups of poly(εCL‐g‐EO) were used to initiate the ATRP of styrene with formation of copolymer with two populations of randomly distributed grafts, that is PEO and polystyrene. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6015–6024, 2006     

Ethylene polymerization by novel Ziegler–Natta‐type catalysts obtained in situ by the oxidative addition of 8‐hydroxyquinoline‐based ligands to bis(1,5‐cyclooctadiene)nickel(0) and methylaluminoxane

Novel catalytic systems, prepared in situ by the oxidative addition of 8‐hydroxyquinoline ligands to bis(1,5‐cyclooctadiene)nickel(0) and activated by methylaluminoxane, were studied in ethylene polymerization. When 8‐hydroxyquinoline was employed, only oligomeric products were obtained. On the contrary, 5,7‐dinitro‐8‐hydroxyquinoline gave linear polyethylene (PE), but with a modest activity. For the catalyst based on 5‐nitro‐8‐hydroxyquinoline, the productivity was largely dependent on the content of free trimethylaluminum (TMA) present in the commercial aluminoxane. The progressive optimization of the TMA/oligomeric methylaluminoxane ratio increased the productivity, which reached 700 kg of PE/(mol of Ni × h), by an order of magnitude. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 200–206, 2006     

Chlorodimethylaluminum-promoted nucleophilic addition of lithium pentamethylcyclopentadienide to aliphatic aldehydes and DDQ-mediated carbon-carbon bond cleavage of the adducts providing the parent aldehydes

Treatment of aliphatic aldehyde with lithium pentamethylcyclopentadienide in the presence of chlorodimethylaluminum provided the corresponding carbinol in excellent yield. The carbinol returns to the parent aldehyde and pentamethylcyclopentadiene by the action of a catalytic amount of 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ).     

Pd-catalyzed arylation/ring-closing metathesis approach to azabicycles

Palladium-catalyzed arylation followed by Grignard addition to imines and ring-closing metathesis, using Grubbs’ catalysts, provides a route to six-, seven-, and eight-membered azabicycles.     

Regio- and Stereocontrolled Nucleophilic Addition Reactions of An Unsymmetrically Disbustituted Butadiene η4-Molybdenum Cationic Complex

The reactions of a new cationic complex, [Cp(CO)₂Mo(η⁴-2-methyl-3-SPh-C₄H₄)]⁺ PF^?₆ (3), with carbon, hydride, and nitrogen nucleophiles were found to give only the C-1 addition products in good yield. The X-ray crystal structures of two of the addition products 4a and 4e confirm the regio- and stereochemistry of the nucleophilic additions.     

Synthese von (±)-Porantherilidin

The synthesis of the title compound is described in detail.

     

Oxazoline as a useful tool in organic synthesis: preparation of 4-aryl-1,2,3,4-tetrahydroisoquinoline alkaloid skeleton

New direct strategy for the synthesis of 4-aryl-1,2,3,4-tetrahydroisoquinolines. The key steps are based on oxazoline chemistry: nucleophilic substitution in an ortho-methoxyphenyloxazoline with a Grignard reagent and a 1,6-conjugate addition of a lithium amide to o-styrylphenyloxazoline.     

Microwave-assisted, solvent-free synthesis of 1-(α- or β-hydroxynaphthyl)-1,2,3,4-tetrahydroisoquinolines by the Mannich reaction

As a new extension of the Mannich reaction of naphthols, 1-(hydroxynaphthyl)-substituted 1,2,3,4-tetrahydroisoquinolines were synthesized by the nucleophilic addition of 1- or 2-naphthol to 3,4-dihydroisoquinolines under solvent-free conditions, using microwave irradiation. The additions to 3-methyl-6,7-dimethoxy-3,4-dihydroisoquinoline proved to be a highly diastereoselective processes, resulting in the cis isomers as the main or the only products.     

Aza-Baylis-Hillman reaction of salicyl N-tosylimines with methyl vinyl ketone, ethyl vinyl ketone or phenyl vinyl ketone

Reactions of salicyl N-tosylimines with methyl vinyl ketone, ethyl vinyl ketone or phenyl vinyl ketone proceeded smoothly under mild conditions to give the corresponding chromanes or aza-Baylis-Hillman adducts in moderate to excellent yields in the presence of phosphine or nitrogen Lewis base.     

Functionalized naphthol[2,3-h] quinoline-7,12-diones

The addition of secondary and primary amines to ethyl (1-amino-9,10-anthraquinon-2-yl)propynoate affords an easily separable mixture of the corresponding ethyl 3-dialkylaminoor 3-alkylamino-3-(1-amino-9,10-anthraquinon-2-yl)acrylate and 3-dialkylamino- or 3-alkylaminonaphthol[2,3-h]quinoline-2(1H), 7,12-trione (in ∼4: 1 ratio). Intramolecular cyclization of the resulting substituted ethyl acrylates results in the formation of 4-dialkylaminoor 4-alkylamino-2-chlorinated pyridine rings. Subsequent nucleophilic substitution of the chlorine atom gives 2-functionalized 4-dialkylamino- or 4-alkylaminonaphtho[2,3-h]quinoline-7,12-diones. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2327–2332, November, 1998.