Rutheniumkatalysierte Synthese von 2,3‐Cyclo[3]dendralenen und komplexer Polycyclen aus Propargylalkoholen

Abstract

Rutheniumkatalysierte Kaskadentransformationen zur Synthese von 2,3‐Cyclo[3]dendralenen und darauf basierende Mehrkomponentenprozesse zum Aufbau komplexer Polycyclen werden vorgestellt. Die Kombination von Allylierungs‐Cyclisierungs‐Sequenzen mit Dien‐transmissiven Diels‐Alder‐Reaktionen ermöglicht den schnellen und selektiven Aufbau naturstoffähnlicher Motive ausgehend von leicht zugänglichen Verbindungen im Eintopfverfahren und eröffnet einen neuen Zugang zu potenziellen Wirkstoffkandidaten.

Ruthenium-catalyzed formation of pyrazoles or 3-hydroxynitriles from propargyl alcohols and hydrazines

“…In accordance with our previously reported results, [12][13][14][15][16][17][18][19][20] substrate activation occurs by initial formation of the chelated π-complex I and its subsequent conversion into alkynyl species II. Secondary substrates are further converted to alkenyl complex III by a 1,2-hydrogen shift.…”

“…[12][13][14][15][16] Saturated tertiary substrates generate diverse addition or substitution products, 13,15,20 whereas tertiary 1-alkenyl propargyl alcohols undergo an allylation/cycloisomerization cascade process. 13,14,[16][17][18][19][20] Herein, we report on a mechanistically related formation of pyrazoles from secondary propargyl alcohols and hydrazines as well as the generation of 3-hydroxynitriles from tertiary substrates applying similar reaction conditions (Scheme 1). Scheme 1.…”

Triaminocyclopentadienyl Ruthenium Complexes – New Catalysts for Cascade Conversions of Propargyl Alcohols

“… [5] Complexes 7 are formed from iminium precursors L 7 as formal ruthenium(II) species, whereas catalysts of type 1 derived from cyclopentadienone precursors L 1 arise as formal ruthenium(0) complexes (Scheme 2 ). [ 4c , 6 ]…”

Control of Chemical Reactions by Using Molecules that Buffer Non‐aqueous Solutions

“…[7][8][9] In our survey of the literature on the reactions of 1,3-cyclohexanedione derivatives reportedb yo ther research groups, we found that the loading amountso f1 ,3-cyclohexanedione weren ot in excess in most cases. [10,11] We reasoned that high loadings of 1,3-cycohexanedione might partially neutralizeb ases or acids depending on the reaction and that 1,3-cycohexanedionew as essentially functioning as ab uffering molecule in organic solvents. We hypothesized that the buffering functiono f1 ,3-cyclohexanedionea nd relatedc ompounds could be used for adjusting conditions to control chemical eventsi nn on-aqueous solutions( Figure 1).…”