An unexpected course of a palladium catalyzed three-component reaction leading to steroid chroman ketals

作者：Mayorquin Torres Martha C; Flores Alamo Marcos; Iglesias Arteaga Martin A^*

来源：Tetrahedron Letters, 2017, 58(36): 3500-3504.

DOI：10.1016/j.tetlet.2017.07.081

• Pd-catalyzed three-component reaction
• Steroid chroman ketals
• NMR
• X-ray diffraction

A previously reported Pd-catalyzed MCR of 4-pentyn-l-ol derivatives with salicylaldehyde and methyl orthoformate follows an unexpected course when carried out with the 5 alpha-and 5 beta-epimers of 4,5-secocholestan-5-ol, leading to chroman ketals. The homologation of the alkynol and the restriction of its conformational equilibrium trigger a drastically different reaction course.

• 出版日期2017-9-6