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Titolo:
STEREOSELECTIVE PREPARATION OF POLYFUNCTIONAL CYCLOPENTANE DERIVATIVES BY RADICAL NICKEL-CATALYZED OR PALLADIUM-CATALYZED CARBOZINCATIONS
Autore:
STADTMULLER H; VAUPEL A; TUCKER CE; STUDEMANN T; KNOCHEL P;
Indirizzi:
UNIV MARBURG,FACHBEREICH CHEM,HANS MEERWEIN STR D-35032 MARBURG GERMANY UNIV MARBURG,FACHBEREICH CHEM D-35032 MARBURG GERMANY
Titolo Testata:
Chemistry
fascicolo: 10, volume: 2, anno: 1996,
pagine: 1204 - 1220
SICI:
0947-6539(1996)2:10<1204:SPOPCD>2.0.ZU;2-9
Fonte:
ISI
Lingua:
ENG
Soggetto:
ZINC EXCHANGE-REACTION; HIGHLY FUNCTIONALIZED COPPER; CONJUGATE ADDITION-REACTIONS; VALENT METAL-COMPLEXES; POLYFUSED RING-SYSTEMS; ORGANOZINC REAGENTS; ENANTIOSELECTIVE ADDITION; OXIDATIVE ADDITION; GRIGNARD-REAGENTS; NITRO-OLEFINS;
Keywords:
ASYMMETRIC CYCLIZATION; CATALYSIS; CYCLOPENTANE; NATURAL PRODUCTS; PALLADIUM COMPLEXES;
Tipo documento:
Review
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
143
Recensione:
Indirizzi per estratti:
Citazione:
H. Stadtmuller et al., "STEREOSELECTIVE PREPARATION OF POLYFUNCTIONAL CYCLOPENTANE DERIVATIVES BY RADICAL NICKEL-CATALYZED OR PALLADIUM-CATALYZED CARBOZINCATIONS", Chemistry, 2(10), 1996, pp. 1204-1220

Abstract

The reaction of 5-hexenyl iodides with diethylzinc (2 equiv) and catalytic amounts of a Pd-II or Ni-II complex like PdCl2(dppf), PdCl2(MeCN)(2), or Ni(acac)(2) results in an efficient ring closure (THF, RT, 2-12h) affording cyclopentylmethylzinc iodides, which, after transmetalation with CuCN . 2LiCl, can be further functionalized by treatment with a range of electrophiles like allylic halides, acyl chlorides, enones, nitro-olefins, ethyl propynoate, and alkynyl halides to yield polyfunctional cyclopentane derivatives. The ring closures occur via radical intermediates, and the stereochemistry of the products can be explained according to the rules for radical cyclizations developed by Beckwith. The preparation of several di- and trisubstituted cyclopentanes has been achieved with high stereoselectivity. Tandem ring closures canbe performed to construct bicyclic or tricyclic ring systems, Cyclizations of iodo-ethylenic and acetylenic esters and ketones can be accomplished, although the high reactivity of acetylenic ketones leads to unexpected cyclization products. The synthetic utility of this method has been demonstrated by an enantioselective synthesis of (+)-methyl epijasmonate and (-)-methyl cucurbate.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 29/03/20 alle ore 12:15:28