Catalytic asymmetric synthesis of acyclic arrays by tandem 1,4-addition-aldol reactions
Catalytic asymmetric synthesis of acyclic arrays by tandem 1,4-addition-aldol reactions
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DOI：
10.1021/ja0651862
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发表时间：
2006-11-22
影响因子：
15
通讯作者：
Feringa, Ben L.
中科院分区：
文献类型：
--
作者：
Howell, Gareth P.;Fletcher, Stephen P.;Feringa, Ben L.
在此，我们报道了由催化不对称有机金属加成引发的串联1，4-加成-羟醛缩合反应中的有效无环立体控制。Grignard试剂以1，4-方式加成到α，β-不饱和硫酯上，生成的烯醇化镁与芳香族或脂肪族醛结合。该方法提供了一系列具有三个连续立构中心的串联产物，具有对相对和绝对立体化学的优异控制。各种非对映异构体的产品已被充分利用单晶X-射线分析和立体控制的起源在这串联协议进行了讨论。该方法的通用性和有效性在首次通过简短路线催化不对称合成（-）-菜豆酸中得到了证明，总收率为54%。
Herein, we report efficient acyclic stereocontrol in tandem 1,4-addition-aldol reactions triggered by catalytic asymmetric organometallic addition. Grignard reagents add to alpha,beta-unsaturated thioesters in a 1,4-fashion and the resulting magnesium enolatesare trapped with aromatic or aliphatic aldehydes. The process provides a range of tandem products bearing three contiguous stereocenters with excellent control of relative and absolute stereochemistry. The various diastereomeric products have been fully characterized using single-crystal X-ray analysis and the origins of stereocontrol in this tandem protocol are discussed. The versatility and efficiency of this methodology are demonstrated in the first catalytic asymmetric synthesis of (-)-phaseolinic acid with 54% overall yield via a short and concise route.