508183-93-5Relevant academic research and scientific papers
Asymmetric conjugate reductions with samarium diiodide: Asymmetric synthesis of (2S,3R)- And (2S,3S)-[2-2H,3-2H]-leucine-(S)- phenylalanine dipeptides and (2S,3R)-[2-2H,3-2H]- phenylalanine methyl ester
Davies, Stephen G.,Rodriguez-Solla, Humberto,Tamayo, Juan A.,Cowley, Andrew R.,Concellon, Carmen,Garner, A. Christopher,Parkes, Alastair L.,Smith, Andrew D.
, p. 1435 - 1447 (2007/10/03)
The highly diastereoselective samarium diiodide and D2O-promoted conjugate reduction of homochiral (E)- and (Z)-benzylidene and isobutylidene diketopiperazines (E)-5,7 and (Z)-6,8 has been demonstrated. This methodology allows the asymmetric synthesis of methyl (2S,3R)-dideuteriophenylalanine 27 in ≥95% de and >98% ee, and (2S,3R)- or (2S,3S)-dideuterioleucine-(S)- phenylalanine dipeptides 37 and 38 in moderate de, 66% and 74% respectively. A mechanism is proposed to account for this process. The Royal Society of Chemistry 2005.
Chiral glycine cation equivalents: N-acyliminium species derived from diketopiperazines
Bull, Steven D.,Davies, Stephen G.,Garner, A. Christopher,O'Shea, Michael D.,Savory, Edward D.,Snow, Emma J.
, p. 2442 - 2448 (2007/10/03)
Studies towards a N,N′-bis(p-methoxybenzyl)diketopiperazine asymmetric glycine cation equivalent for the synthesis of homochiral α-amino acids are described. The oxidation of enolate 3 with molecular oxygen provides either a mixture of hydroxylated diketopiperazines 7 and 8 or trione 10 depending upon the reaction conditions. The nucleophilic reduction of trione 10 and the reaction of acetoxy N-acyliminium ion precursors 5 and 6, derived from 7 and 8, with allyltrimethylsilane and boron trifluoride etherate is examined and a model for the stereoselectivity observed in these additions is presented.
