作者:Stephen G. Davies、Deri G. Hughes、Rebecca L. Nicholson、Andrew D. Smith、Angela J. Wright
DOI:10.1039/b402437k
日期:——
the primary [small beta]-amino ester via hydrogenolysis, oxazolidinone formation with C(2)-retention by treatment with diphosgene and chemoselective ester reduction furnishes (4R,5R)-cytoxazone. The synthesis of the C(5)-epimer, (4R,5S)-epi-cytoxazone in 44% overall yield, has also been completed via a protocol involving N-Boc protection of the primary [small beta]-amino ester, utilization of the N-Boc
(4R,5R)-Cytoxazone分四个步骤制备,总收率61%,ee≥98%。将(R)-N-苄基-N- [小α]-甲基苄基酰胺锂加到(E)-3-(对甲氧基苯基)丙-2-烯酸叔丁酯中,然后用(+ )-(樟脑磺酰基)恶氮丙啶得到叔丁基(2R,3R,[小αR] -2-羟基-3-(对甲氧基苯基)-3-(N-苄基-N- [小α]-甲基苄基氨基)丙酸酯> 98%de 随后的N-苄基脱氢反应通过氢解,恶唑烷酮形成与C(2)保留通过双光气和化学选择性酯还原处理的初级β-氨基酯提供(4R,5R)-cytoxazone。以44%的总收率合成C(5)-顶基,(4R,5S)-表三