Protecting‐Group‐Free Diastereoselective Total Synthesis of (±)‐6‐epi‐Cleistenolide and Chemoenzymatic Synthesis of (–)‐6‐epi‐Cleistenolide. Issue 36 (31st October 2014) - Mahajan, Pankaj S.
Abstract: A short, efficient, practical, and protecting‐group‐free diastereoselective total synthesis of (±)‐6‐ epi ‐cleistenolide (1 ) has been achieved in five steps in 60 % overall yield. The use of a chemoenzymatic approach also gave (–)‐6‐ epi ‐cleistenolide (1 ) (>99.9 % ee ). The Achmatowicz reaction, chemoselective oxidation of a hemiacetal, diastereoselective 1, 3‐ anti reduction of a β‐hydroxy ketone, and enzymatic resolution of a 1, 3‐diol are the key features of this linear total synthesis. The synthetic strategy demonstrated in this paper could be extended for an asymmetric total synthesis of (–)‐cleistenolide (1 ) and related biologically active natural products. Abstract : A short, efficient, practical, and protecting‐group‐free diastereoselective total synthesis of 6‐ epi ‐(±)‐cleistenolide (1 ) has been achieved in five steps in 60 % overall yield. The use of a chemoenzymatic approach also gave (–)‐6‐ epi ‐cleistenolide (1 ) with >99.9 % ee .