193416-20-5Relevant academic research and scientific papers
Enantioselective total synthesis of (-)-denticulatins A and B using a novel group-selective aldolization of a meso dialdehyde as a key step
De Brabander, Jef,Oppolzer, Wolfgang
, p. 9169 - 9202 (2007/10/03)
The diastereoselective synthesis of (-)-denticulatin A (1a) was achieved for the first time in 9 steps (41% yield) based on a novel group-selective aldolization of a meso dialdehyde as a key step. The inherent chirality present in bornanesultam 4 was thus transmitted to the five stereocenters spanning C4-C8 in key intermediate 8. In addition, denticulatin B (1b) was obtained from the common intermediate 8 en route to denticulatin A in 10 steps and 35% overall yield.
Non-destructive Removal of the Bornanesultam Auxiliary in α-Substituted N-Acylbornane-10,2-sultams under Mild Conditions: An Efficient Synthesis of Enantiomerically Pure Ketones and Aldehydes
Oppolzer, Wolfgang,Darcel, Christophe,Rochet, Patrick,Rosset, Stephane,Brabander, Jef De
, p. 1319 - 1337 (2007/10/03)
α-Substituted N-acylbornane-10,2-sultams 6, 9, and 10 can be converted into enantiomerically pure ketones 5, 13, and 14, respectively, via a two-step procedure involving a known mercaptolysis reaction followed by an -mediated coupling of the resulting S-benzyl thioesters with Grignard reagents.Furthermore, enantiomerically pure aldehydes 23 can be obtained from α-substituted N-acylbornane-10,2-sultams 6 via a one-step reduction with (i-Bu)2AlH.No epimerization at the α-chiral center is observed during the cleavage reaction whereby the chiral auxiliary, bornane-10,2-sultam 1 or ent-1, was recovered.By using this methodology, several natural products or precursors thereof can be prepared.
