Complete reversal of enantioselection using oxazoline-containing Schiff base ligands derived from l-serine in enantioselective addition of diketene to aldehydes
摘要:
Starting from one stereogenic center (in this case from L-serine), we obtained two chiral Schiff bases possessing oxazoline moieties, each of which recognized a different enantioface of aldehydes with a high enantionteric excess [up to 93% ee (R) and 89% ee (S)] in the addition reaction of diketene to 2-furfural. (c) 2006 Elsevier Ltd. All rights reserved.
Highly efficient preparation of optically active 5-hydroxy-3-oxoesters by enantioselective reaction of diketene with aldehydes promoted by novel chiral Schiff base-titanium alkoxide complexes
作者:Masahiko Hayashi、Kiyoshi Tanaka、Nobuki Oguni
DOI:10.1016/0957-4166(95)00230-m
日期:1995.8
Optically active 5-hydroxy-3-oxoesters 1 can be obtained in up to 91% enantiomeric excess (e.e.) by the enantioselective reaction of diketene with aldehydes promoted by novel chiral Schiff base-titanium alkoxide complexes.
Catalytic Enantioselective Reaction of Diketene with Aldehydes Catalyzed by Chiral Schiff Base-Titanium Alkoxide Complexes
作者:Nobuku Oguni、Kiyoshi Tanaka、Hajime Ishida
DOI:10.1055/s-1998-1744
日期:1998.6
The catalytic enantioselective reaction of diketene with aldehydes was achieved by the use of a catalytic amount (20 mol%) of chiral Schiff base to afford the corresponding 5-hydroxy-3-oxoesters with high enantioselectivity.
The Asymmetric Maitland−Japp Reaction and Its Application to the Construction of the C1−C19 <i>Bis</i>-pyran Unit of Phorboxazole B
作者:Paul A. Clarke、Soraia Santos、Nimesh Mistry、Laurence Burroughs、Alexander C. Humphries
DOI:10.1021/ol102860r
日期:2011.2.18
The synthesis of the C1-C19 bis-pyran unit of phorboxazole B has been achieved. The key pyran rings were constructed by means of an asymmetric Maitland-Japp reaction and a second Maitland-Japp resolution/cyclization reaction. The longest linear sequence was 14 steps, and the C1-C19 bis-pyran unit was formed in an impressive 10.4% yield.
Complete reversal of enantioselection using oxazoline-containing Schiff base ligands derived from l-serine in enantioselective addition of diketene to aldehydes
Starting from one stereogenic center (in this case from L-serine), we obtained two chiral Schiff bases possessing oxazoline moieties, each of which recognized a different enantioface of aldehydes with a high enantionteric excess [up to 93% ee (R) and 89% ee (S)] in the addition reaction of diketene to 2-furfural. (c) 2006 Elsevier Ltd. All rights reserved.
Enantioselective addition Of diketene to aldehydes promoted by chiral schiff base—titanium alkoxide complex. Application to asymmetric synthesis of potential inhibitors of HMG coenzyme reductase
Highly enantioselective addition of diketene to aldehydes was achieved by using novel Schiff base—titanium alkoxide complexes. Up to 92% ee of 5-hydroxy-3-oxoesters was obtained. This procedure provides an efficient method for the asymmetric synthesis of potential inhibitors of HMG coenzyme reductase.