Enantioselective Synthesis of the C<sub>10</sub>–C<sub>20</sub> Fragment of Fusicoccin A
作者:Anja Richter、Christian Hedberg、Herbert Waldmann
DOI:10.1021/jo201020v
日期:2011.8.19
are a nonconventional Cr-catalyzed allylic oxidation of a protected intermediate cylcopentenone, a diastereoselective addition of a propenyl Grignard/CeCl3 reagent to the unmasked cyclopentenone, and an asymmetric hydroboration of the isopropenyl substituent. The protected and suitably functionalized C-ring fragment paves the way to explore further the total synthesis of fusicoccin A.
据报道,三环二萜品富西辛A的完全保护的C环片段的合成。总共九个步骤获得了所需的环戊烯基卤化物5a,b。合成序列的关键转变是受保护的中间体环戊烯酮的非常规Cr催化的烯丙基氧化,丙烯基Grignard / CeCl 3试剂向非掩蔽的环戊烯酮的非对映选择性加成以及异丙烯基取代基的不对称硼氢化。受保护的和适当官能化的C环片段为进一步探索夫西考辛A的全合成铺平了道路。