A convenient formation of aporphine core via benzyne chemistry: conformational analysis and synthesis of (R)-aporphine

Biologically active isoquinoline alkaloids covering 2014–2018

“…40 (+)-N-Formylnorglaucine (114) was reported from Unonopsis stipitata. 62 Four new phenyl-C 1 substituted aporphine alkaloids, 6aR-2′-methoxycarbonylthaliadine (115), 6aR-2′carboxylthaliadine (116), 6aR-3-methoxyhernandalinol (117), 6aS-1,3,10-trimethoxynatalamine (118), together with three known isoquinoline alkaloids 89, predicentrine (119), and thaliadine (120) were isolated from the whole herb of T. cirrhosum. 43 Glaucine 121 wangii 46 ( Figure 5).…”

“…Aporphine alkaloids are a large group of isoquinolines that generally possess a characteristic tetracyclic ring system (rings A–D) with a nitrogen in ring B 119 . The structures of the aporphine alkaloids can be classified into subtypes, including simple aporphines, their dehydro derivatives, oxoaporphines, miscellaneous aporphinoids, and dimeric aporphinoid alkaloids 120–123 …”

Recent Advances for the C–C and C–N Bond Formation in the Synthesis­ of 1-Phenethyl-tetrahydroisoquinoline, Aporphine, Homoaporphine­, and β-Carboline Alkaloids

“…112 During the 1980s and 1990, Castedo and co-workers developed the synthesis of various aporphinoid alkaloids based on intermolecular aryne Diels-Alder cycloadditions. 113,114 In 2015, Raminelli and co-workers 115 developed a novel protocol, where the total synthesis of (R)-aporphines was accomplished by exploring the properties of the 1-methyleneisoquinoline 153, as a nonpolar diene, and its [4+2]-cycloaddition reaction with reactive benzynes derived from 154. This approach was extended to the synthesis of (±)-nornuciferine (158), (±)-nuciferine (159), (±)-trimethoxynoraporphine (166), (±)-O-methylisothebaine (167), and (±)-zanthoxyphylline iodide (168).…”

“…in a sequence of well-established reactions (Nacetylation and Bischler-Napieralski reactions) followed by an additional N-acetylation with trifluoroacetic anhydride to give 153 in an overall yield of 61% (Scheme 22) 115. Scheme 22 Synthesis of the key intermediateThe reaction 153 with benzyne 155, prepared in situ from 2-(trimethysilyl)phenyl triflate(154) and CsF, proceeded through a sequence of transformations involving a [4+2]-cycloaddition reaction followed by a hydrogen migration in 156 that led the formation of the aporphine skeleton 157.…”

Química Orgânica no Brasil: sua contribuição na síntese total de produtos naturais desde a fundação da SBQ

“…A preparação estereosseletiva da mesma, efetuada em apenas 3 etapas 22 , teve como material de partida um diazo-oxo-alquilfosfonato desenvolvido em laboratório local 23 . Já a síntese da (-)-aporfina 24 Dentre os alvos sintéticos escolhidos pela comunidade de orgânicos brasileiros, não poderia faltar a classe dos policetídeos ou oxigenados, onde a presença de hidroxilas, carbonilas e duplas ligações congregam uma grande diversidade de produtos naturais. Um dos exemplos iniciais da capacidade da comunidade sintética nacional em alcançar a construção destes compostos foi a (+/-)-pirenoforina.…”