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

Article abstract of DOI:10.1002/hlca.19970800502

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.