Acyclic stereochemical control using hexacarbonyldicobalt stabilized propargyl cation. A highly stereoselective route to 1β-methylcarbapenem precursors.
作者:J.Siva Rrasad、Lanny S. Liebeskind
DOI:10.1016/s0040-4039(00)95993-8
日期:1987.1
is described. Hydride reduction of a hexacarbonyldicobalt stabilized propargyl cation derived from a 4-acyl-2-azetidinone prepared using the Weinreb ketone synthesis proceeds with complete stereochemical control to a 1β-methylcarbapenem precursor bearing an alkynyl unit. The alkyne is readily elaborated to (3S,4R)-3-[(1R)-1-t-butyldimethylsilyloxyethyl]-4-[(1R)-1-methyl-3-methoxycarbonyl-2-oxoprop
描述了对1β-甲基咔ap烯前体的高度立体选择性的途径。使用Weinreb酮合成制备的由4-酰基-2-氮杂环丁酮衍生的六羰基二钴稳定的炔丙基阳离子的氢化物还原反应,在完全立体化学控制下,可转化为带有炔基单元的1β-甲基卡宾烯前体。炔很容易被修饰成(3S,4R)-3-[(1R)-1-叔丁基二甲基甲硅烷基氧乙基] -4-[(1R)-1-甲基-3-甲氧基羰基-2-氧丙基] -2-氮杂环丁烷- 2-一或氢化并氧化裂解为(3S,4S)-3-[(1R)-1-叔丁基二甲基甲硅烷基氧乙基] -4-[(1R)-1-羧乙基]-氮杂环丁烷-2-一。