Tetrahedron letters

The thiopyran route to polypropionates revisited: Selective syn and anti aldol reactions via 3, 6-dihydro-4-trimethylsilyloxy-2H-thiopyran

DE Ward, CC Man, C Guo

文献索引：Ward, Dale E.; Man, Chuk; Guo, Cheng Tetrahedron Letters, 1997 , vol. 38, # 13 p. 2201 - 2202

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被引用次数: 26

摘要

Aldol reaction of the amine free Li enolate of tetrahydro-4H-thiopyran-4-one with 1, 4-dioxa- 8-thiaspiro [4.5] decane-6-carboxaldehyde gives mainly the 2, 3-anti-3, 4-syn aldol (7: 1) in good yield; reaction of the LDA generated lithium enolate proceeds poorly. Using the trimethylsilyl enol ether and TiCl4 gives the 2, 3-syn-3, 4-syn aldol (> 10: 1). The adducts can be used for polypropionate synthesis.