New P,N Ligands for asymmetric Ir-catalyzed reactions
New P,N Ligands for asymmetric Ir-catalyzed reactions
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DOI：
10.1002/anie.200351936
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发表时间：
2003-01-01
影响因子：
16.6
通讯作者：
Knochel, P
中科院分区：
文献类型：
--
作者：
Bunlaksananusorn, T;Polborn, K;Knochel, P
近年来，不对称金属催化新配体的制备导致了几类新的手性配体的发现。[1]最近，我们报道了tBuOK催化的亲核试剂（羰基衍生物和膦）与各种官能化烯烃的加成反应。[2]在此，我们报告了使用这种方法从现成的手性结构单元例如d-（+）-樟脑（7）和（R）-（+）-诺皮诺酮（8）制备新的手性P，N配体[3] 1-6（参见方案2）。我们表明，这些配体可用于高对映选择性Ir催化氢化。已知的烯基三氟甲磺酸酯[4] 9经历平滑的Negishi交叉偶联反应[5]，以35-78%的产率[6]得到所需的2-烯基吡啶13 a-c，以65%的产率得到2-烯基喹啉14。类似地，烯基三氟甲磺酸酯10以69-85%的产率转化为2-烯基吡啶15 a-c（方案1）.用二苯基膦（Ph 2 PH）、二环己基膦（Ph 2 PH）、（（c-C6H11）2PH），或二苯基磷烷氧化物（Ph 2 P（O）H）在二甲基亚砜（DMSO）或N-甲基吡咯烷酮（NMP）中在催化量的tBuOK（20摩尔%）以55-93%产率提供膦氧化物16 a-d和17 a-b。[2c]在甲苯中用HSiCl 3/Et 3 N还原膦氧化物[7]，以60-92%产率得到所需的P，N配体1-6（方案2）。通过NOESY NMR实验和X射线晶体结构分析确定了P，N配体的相对立体化学（参见支持信息）。[八]《中国日报》
The preparation of new ligands for asymmetric metal catalysis has led in recent years to the discovery of several new classes of chiral ligands.[1] Recently, we reported tBuOK-catalyzed addition reactions of nucleophiles (carbonyl derivatives and phosphanes) to a variety of functionalized alkenes.[2] Herein, we report the use of this method for the preparation of the new chiral P, N ligands [3] 1–6 (see Scheme2) from readily available chiral building blocks such as d-(+)-camphor (7) and (R)-(+)-nopinone (8). We show that these ligands can be used for highly enantioselective Ir-catalyzed hydrogenations. The known alkenyl triflate [4] 9 underwent smooth Negishi cross-coupling reactions [5] to afford the desired 2-alkenyl pyridines 13 a–c in 35–78% yield [6] and the 2-alkenyl quinoline 14 in 65% yield. Similarly, the alkenyl triflate 10 was converted into the 2-alkenyl pyridines 15 a–c in 69–85% yield (Scheme 1).The treatment of these unsaturated pyridines with diphenylphosphane (Ph2PH), dicyclohexylphosphane ((c-C6H11) 2PH), or diphenylphosphane oxide (Ph2P (O) H) in dimethyl sulfoxide (DMSO) or N-methylpyrrolidinone (NMP) in the presence of a catalytic amount of tBuOK (20 mol%) provided the phosphane oxides 16 a–d and 17 a–b in 55–93% yield.[2c] The phosphane oxides were reduced with HSiCl3/Et3N in toluene [7] to give the desired P, N ligands 1–6 in 60–92% yield (Scheme 2). The relative stereochemistry of the P, N ligands was established by NOESY NMR experiments and by X-ray crystal-structure analysis (see Supporting Information).[8]