Chiral induction in the sysnthesis of 4,4-dimethyl-1-phenylpenta-1,2-diene (1-Ph-3-t-Bu-allene) catalyzed by chiral phosphine complexes of palladium
作者:Win de Graaf、Jaap Boersma、Gerard van Koten、Cornelis J. Elsevier
DOI:10.1016/0022-328x(89)85013-2
日期:1989.11
lene) (2) has been prepared by a palladium-catalyzed cross-coupling reaction between either in situ prepared 4,4-dimethylpenta-1,2-dienylzinc chloride and iodobenzene (Route A) or 1-bromo-4,4-dimethylpenta-1,2-diene and phenylzinc chloride (Route B). Several palladium complexes with known chiral phosphine, phosphine-amine and diphosphine ligands were used as chiral catalysts. The highest enantiomeric
通过钯催化的原位制备的4,4-之间的交叉偶联反应制备了4,4-二甲基-1-苯基戊基1,2-二烯(1-苯基-3-叔丁基丙二烯)(2)甲基二甲基-1,2-二烯基氯化锌和碘苯(途径A)或1-溴-4,4-二甲基戊-1,2-二烯和苯基氯化锌(途径B)。具有已知手性膦,膦-胺和二膦配体的几种钯配合物被用作手性催化剂。通过路线A在氯化钯与(R,R)-2,3- O-异亚丙基-2,3-二羟基-1,4-双(二苯基膦基)的络合物的催化下获得最高对映体过量(25%ee))丁烷,“(R,R)-diop”。当复数Pd”(R,R-diop” 2的使用似乎与温度,催化剂的量和试剂的比例无关。但是,当使用镁或铜试剂代替锌试剂时,配置相反(3–10%ee)。建议的中间体PdIPh“(R,R)-diop”是通过用PdIPh(tmeda)(tmeda = N,N,N',N',-四甲基乙二胺)处理一当量的(R,R)-diop来制备的,并进行了研究通过31