Hinkle Robert J, Lian Yajing, Speight Lee C, Stevenson Heather E, Sprachman Melissa M, Katkish Lauren A, Mattern M Christa
Department of Chemistry, the College of William & Mary, P. O. Box 8795, Williamsburg, VA 23187-8795, USA.
Tetrahedron. 2009 Aug 22;65(34):6834-6839. doi: 10.1016/j.tet.2009.06.083.
The rapid synthesis of cis-2,6-disubstituted dihydropyrans is achieved in a three-component, one-pot cascade reaction. BiBr(3)-ediated addition of ketene silyl acetals or silyl enol ethers to beta,gamma-unsaturated cis-4-trimethylsilyl-3-butenal provides a Mukaiyama aldol adduct containing a vinylsilane moiety tethered to a silyl ether. Addition of a second aldehyde initiates a domino sequence involving intermolecular addition followed by an intramolecular silyl-modified Sakurai (ISMS) reaction. Isolated yields of this one-pot reaction vary from 44 to 80% and all compounds were isolated as the cis-diastereomers (10 examples).
通过三组分一锅法串联反应可实现顺式-2,6-二取代二氢吡喃的快速合成。在BiBr₃介导下,烯酮硅基缩醛或烯醇硅醚与β,γ-不饱和顺式-4-三甲基硅基-3-丁烯醛加成,得到一个含有与硅醚相连的乙烯基硅烷部分的Mukaiyama羟醛加成物。加入第二种醛引发一个多米诺序列,包括分子间加成,随后是分子内硅基修饰的Sakurai(ISMS)反应。该一锅法反应的分离产率在44%至80%之间,所有化合物均以顺式非对映异构体形式分离得到(10个实例)。