Metal-Mediated Synthesis of Medium-Sized Rings

Grubb’s and Wilkinson catalyzed reactions of 2-phenyl-3-vinyl substituted 2H-azirines

“…20 To date, this catalyst is routinely used for ring closing metathesis (RCM), cross metathesis (CM), and other metathesis-type reactions. The commercial availability and effectiveness of the Grubbs' catalyst now allow olefin metathesis strategies to be viewed as practical methods for the synthesis of medium size ring, 21 spiro and polycyclic systems 22 and natural products. 23 A growing number of newly discovered catalytic processes mediated by Grubbs' carbene complex also broaden its synthetic utility beyond olefin metathesis.…”

Métodos de preparação de lactonas de anel médio

“…É conhecido que compostos de anel médio, inclusive lactonas, são mais difíceis de se preparar por reações de ciclização que seus homólogos inferiores ou superiores 13,14 . Tal dificuldade reside no fato de que a ciclização é desfavorecida tanto por fatores entrópicos quanto por fatores entálpicos, como discutido por Illuminati e Mandolini 15 .…”

Ruthenium‐Catalyzed Ring‐Closing Metathesis: Recent Advances, Limitations and Opportunities

“…Cogent overviews of the applications of RCM [2][3][4][5] in organic synthesis have appeared: of these, Armstrong's review gives a particularly useful analysis of the scope and limitations of early and late-metal catalyst systems, much of which remains relevant to catalysts subsequently developed [5]. Other recent reviews describe synthesis of specific target classes via RCM: these include medium-sized rings [37,38], heterocyclic rings containing phosphorus [6], sulfur [6,39], oxygen [7], or nitrogen [7]; and biologically relevant targets, including the epothilones [9], carbohydrate derivatives [10], several natural products [2,8], and macrocycles containing (E)-alkene units [40]. Overviews of domino [11,12] and tandem [41][42][43][44] metathesis strategies have also recently appeared (for mechanisticallybased definitions of these and related terms, see Ref.…”