Lewis Acid Catalyzed Intramolecular [4+2] Cycloaddition of In Situ Generated Aza‐Quinone Methides for the Stereoselective Synthesis of Furo/pyrano[3,2‐
<i>c</i>
]tetrahydroquinolines
作者:Santosh J. Gharpure、Dharmendra S. Vishwakarma
DOI:10.1002/ejoc.201901598
日期:2020.11.30
A TMSOTf‐catalyzed intramolecular [4+2] cycloaddition of in situ generated aza‐o‐quinone methide acts as an expedient, stereoselective access to cis/trans‐fused furo‐/pyrano[3,2‐c]tetrahydroquinolines with excellent yields and diastereoselectivity.
TMSOTf催化的原位生成的氮杂-邻-醌甲基化物的分子内[4 + 2]环加成反应,是对顺式/反式融合的呋喃-/吡喃并[3,2- c ]四氢喹啉的便捷,立体选择途径,并具有优异的收率和非对映选择性。
Scandium-Catalyzed Cascade Cyclization to Produce Cyclobutane-Fused Tetrahydroquinoline, Chromane, Thiochromane, and Tetrahydronaphthalene Derivatives
We have succeeded in the highly diastereoselective synthesis of cyclobutane‐fused multi‐cyclic compounds using a scandium‐catalyzed cascade cyclization. Using 3–10 mol% of scandium(III) triflate [Sc(OTf)3], various cyclobutane‐fused tetrahydroquinoline derivatives as well as its chromane, thiochromane, and tetrahydronaphthalene analogues were obtained in good to excellent yields. Derivatizations of
The catalyst-controlled diversity-oriented synthesis of spirohydroquinoline-indandiones and 3-methylenehydroquinoline-indandiones from ortho-sulfonamidophenyl-substituted para-quinone methides and allylidene-indandiones is reported. The strategies utilized an organobase such as DMAP or TMG to control the reaction pathway chemoselectively, furnishing the corresponding products in 40–99% yields with