113626-45-2Relevant academic research and scientific papers
ENANTIOSELECTIVE ALDOL CONDENSATIONS: THE USE OF KETONE BORON ENOLATES WITH CHIRAL LIGANDS ATTACHED TO BORON.
Paterson, Ian,Lister, M. Anne,McClure, Cynthia K.
, p. 4787 - 4790 (1986)
Aldol condensation between diethylketone and simple aldehydes using (Ipc)2BOTf/iPr2NEt in CH2Cl2 gives syn adducts in good ee (66-90percent) and with high diastereoselectivity (>=90percent).Other chiral dialkylboron triflate reagents examined give lower ees.
Diastereoselective aldol and reformatsky reactions of α-halo carbonyl compounds and aldehydes mediated by Titanium(II) Chloride
Kagayama,Igarashi,Shiina,Mukaiyama
, p. 2579 - 2585 (2007/10/03)
Highly diastereoselective aldol reactions of α-bromo ketones with several aldehydes were successfully carried out by using a combination of titanium(II) chloride and copper or sodium iodide in dichloromethane-pivalonitrile at low temperature. Similarly, Reformatsky reactions of α-bromo thioester with aliphatic aldehydes proceeded to afford β-hydroxy thioesters in good yields under mild conditions.
ENANTIO- AND DIASTEREOSELECTIVE ALDOL REACTIONS OF ACHIRAL ETHYL AND METHYL KETONES WITH ALDEHYDES: THE USE OF ENOL DIISOPINOCAMPHEYLBORINATES.
Paterson, Ian,Goodman, Jonathan M.,Lister, M. Anne,Schumann, Russell C.,McClure, Cynthia K.,Norcross, Roger D.
, p. 4663 - 4684 (2007/10/02)
Enol diisopinocampheylborinates, derived from achiral ethyl and methyl ketones by enolisation in the presence of tertiary amine bases (iPr2NEt or Et2N), undergo enantio- and diastereoselective aldol reactions with aldehydes.The reagents employed, (+)- and (-)-(Ipc)2BOTf, are easily prepared in enantiomerically pure form in two steps from (-)- and (+)-α-pinene, respectively.The aldol reaction between ethyl ketones and aldehydes using (+)- or (-)-(Ipc)2BOTf/iPr2NEt in dichloromethane gives, via the derived chiral Z-enol borinates, syn-α-methyl-β-hydroxy ketones in good enantiomeric excess (66-93percent ee) and with high diastereoselectivity (>95percent).In contrast, the anti-selective aldol reaction of diethylketone via the isomeric E-enol diisopinocampheylborinate (by enolisation with (-)-(Ipc)2BCl) with methacrolein proceeds with negligible enantioselectivity.Use of both the triflate and chloride reagents in the aldol reaction of methyl ketones with aldehydes gives β-hydroxy ketones in moderate enantiomeric excess (53-78percent ee) with a reversal in the enantioface selectivity of the aldehyde compared to the corresponding ethyl ketone syn aldol.This variable selectivity is interpreted as evidence for the participation of competing chair and boat transition states.Other chiral dialkylboron triflate reagents investigated led to reduced enantioselectivities in diethylketone-aldehyde aldol reactions.
