85100-10-3Relevant academic research and scientific papers
Reductive aldol-type reaction of α,β-unsaturated esters with aldehydes or ketones in the presence of Rh catalyst and Et2Zn
Sato, Kazuyuki,Isoda, Motoyuki,Tokura, Yoriko,Omura, Keiko,Tarui, Atsushi,Omote, Masaaki,Kumadaki, Itsumaro,Ando, Akira
, p. 5913 - 5915 (2013)
The reaction of RhCl(PPh3)3 with Et2Zn easily generated a rhodium-hydride complex (Rh-H) that added to α,β-unsaturated esters to form rhodium enolate complexes by formal 1,4-reduction. These rhodium enolates gave the corre
Oxovanadium(IV) complex-mediated catalysis in Mukaiyama-type aldol additions
Chen, Chien-Tien,Hon, Sang-Wen,Weng, Shiue-Shien
, p. 816 - 818 (2007/10/03)
Condensation of vanadyl sulfate with 2,2'-biphenol in the presence of N- containing ligands provides oxovanadium(IV) complexes which serve as efficient catalysts in Mukaiyama aldol reactions to afford aldol products in 52-100% yields with diastereoselecti
Acyclic Stereoselection. 36. Simple Diastereoselection in the Lewis Acid Mediated Reactions of Enol Silanes with Aldehydes
Heathcock, Clayton H.,Davidsen, Steven K.,Hug, Kathleen T.,Flippin, Lee A.
, p. 3027 - 3037 (2007/10/02)
The Lewis acid mediated aldol reactions of enol silanes with aldehydes have been investigated.The effects of enol silane structure, both nature of the ligand at the silyloxy carbon and the geometry of the double bond, the aldehyde structure, and the nature of the Lewis acid have been studied.In general, the reactions of prochiral enol silanes with prochiral aldehydes show little simple diastereoselection (Table I).An exception is Z enol silane 7, derived from ethyl tert-butyl ketone, which shows synthetically useful anti selectivity.Enol silane 36 may therefore be used as an anti-selective propionate equivalent.The chiral α-alkoxy aldehyde 43 shows a high diastereofacial preference in its reactions with enol silanes 42c and 42d provided a Lewis acid capable of expanding its coordination beyond four is used (TiCl4 or SnCl4) (Table II).However, with the related ketene acetal 41b, only modest diastereofacial selectivity is seen (Table II).Aldehyde 43 also shows a high diastereofacial preference, in the chelation-controlled sense, in its reactions with prochiral enol silanes 5-9.However, the simple diastereoselection observed in the latter reactions (Table III) is quite different from that observed in the reactions of prochiral aldehydes with the same enol silanes.For example, enol silane 7, which shows good anti selectivity in its reactions with prochiral aldehydes, gives a 15:1 mixture of the two syn aldols in its reaction with 43; while the reverse is true with the propiophenone-derived enol silanes 8 and 9.Finally, the results obtained in this study, along with those reported by other investigators, have been formulated into a coherent mechanistic rationale involving open transition states of the sort depicted in Figures 1 and 3.
STEREOCONTROLLED ALDOL REACTIONS OF BUTYROLACTONE:ERYTHRO-SELECTIVITY VIA HIGH COORDINATION ZINC COMPLEXES
Widdowson, D.A.,Wiebecke, G.H.,Williams, D.J.
, p. 4285 - 4288 (2007/10/02)
The stereoselection of the lithium catalysed aldol reaction of benzaldehyde and γ-butyrolactone is reversed by zinc ions.The intermediacy of octahedral or square pyramidal zinc complexes is invoked to explain these observations.
