A novel approach for total synthesis of cryptophycins via asymmetric crotylboration protocol
作者:Ulhas P. Dhokte、Vien V. Khau、Darrell R. Hutchison、Michael J. Martinelli
DOI:10.1016/s0040-4039(98)01994-7
日期:1998.11
Acyclic and a highly efficient stereoselective CC bond formation of aldehyde3 with the crotylboron reagent4, derived from (−)-α-pinene, provided a homoallylic alcohol6 in ≥99% enantio-(ee) and diastereomeric excess (de). The alcohol6 was linearly converted into the desired Fragment A10 of cryptophycins in seven steps. This enantiomerically pure Fragment A was conveniently and efficiently coupled with
与衍生自(-)-α-derived烯的巴豆基硼试剂4形成醛3的无环且高效的立体选择性CC键,可提供≥99%对映体(ee)和非对映体过量(de)的均烯丙基醇6。通过七个步骤将醇6线性转化为所需的隐藻霉素片段A 10。该对映体纯的片段A方便且有效地与其他三个片段,即B,C和D偶联,并提供了所需的隐藻霉素A衍生物(LY404291)。进一步阐述了LY404291中的末端双键以提供末端环氧化物LY404292和隐藻素。51和52。