Development of chiral nucleophilic pyridine catalysts: Applications in asymmetric quaternary carbon synthesis
Development of chiral nucleophilic pyridine catalysts: Applications in asymmetric quaternary carbon synthesis
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DOI：
10.1021/ja037223k
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发表时间：
2003-11-05
影响因子：
15
通讯作者：
Vedejs, E
中科院分区：
文献类型：
--
作者：
Shaw, SA;Aleman, P;Vedejs, E
TADMAP（1a）是一种新的手性DMAP催化剂，它将C（3）-苄基三苯甲基置于吡啶环的一面，而C（3）-苄基乙酰氧基则在另一面形成手性环境。TADMAP由三苯乙酸和（二甲氨基）吡啶分四步制备（总收率37%），并使用邻苯二磺酸进行拆分。TADMAP催化恶唑基苯基碳酸酯4重排为吖内酯5，呋喃基苯基碳酸酯8重排为呋喃酮9，苯并呋喃基碳酸酯11 a和11 b重排为苯并呋喃酮12 a和12 b，吲哚基碳酸酯11和11 d重排为羟吲哚12和12 d。产物以良好的产率形成，并且在大多数情况下，在新形成的季碳上具有实际水平的对映异构体过量。
TADMAP (1a), a new chiral DMAP catalyst, has been designed to place a C(3)-benzylic trityl group over one face of the pyridine ring, while a C(3)-benzylic acetoxy group creates a chirotopic environment on the other face. TADMAP was prepared in four steps (37% overall) from triphenylacetic acid and (dimethylamino)pyridine and was resolved using camphorsulfonic acid. TADMAP catalyzes the enantioselective rearrangement from oxazolyl phenyl carbonates4to azlactones5, from furanyl phenyl carbonate8to the furanone9, from the benzofuranyl carbonates11aand11bto benzofuranones12aand12b, and from the indolyl carbonates11cand11dto oxindoles12cand12d. The products are formed in good yield and, in most cases, with practical levels of enantiomer excess at the newly formed quaternary carbon.