Jung Myunggi, Muir Joanna E, Lindsay Vincent N G
Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, North Carolina 27695, United States.
Tetrahedron. 2023 Mar 21;134. doi: 10.1016/j.tet.2023.133296. Epub 2023 Feb 2.
A novel approach for the formation of the highly strained spiro[3.3]heptan-1-one motif was developed through the reaction of 1-sulfonylcyclopropanols and lithiated 1-sulfonylbicyclo[1.1.0]butanes. Following initial nucleophilic addition to the cyclopropanone formed , the resulting 1-bicyclobutylcyclopropanol intermediate is prone to a 'strain-relocating' semipinacol rearrangement in the presence of acid, directly affording the substituted spiro[3.3]heptan-1-one. The process is shown to be fully regio- and stereospecific when starting from a substituted cyclopropanone equivalent, leading to optically active 3-substituted spiro[3.3]heptan-1-ones. The reaction likely proceeds via initial protonation of the bicyclobutyl moiety followed by [1,2]-rearrangement of the resulting cyclopropylcarbinyl cation.
通过1-磺酰基环丙醇与锂化的1-磺酰基双环[1.1.0]丁烷反应，开发了一种形成高张力螺[3.3]庚烷-1-酮基序的新方法。在最初对形成的环丙酮进行亲核加成之后，所得的1-双环丁基环丙醇中间体在酸存在下易于发生“应变重排”半频哪醇重排，直接得到取代的螺[3.3]庚烷-1-酮。当从取代的环丙酮类似物开始时，该过程显示出完全的区域和立体特异性，从而得到光学活性的3-取代螺[3.3]庚烷-1-酮。该反应可能首先通过双环丁基部分的质子化，然后是所得环丙基甲基阳离子的[1,2]重排进行。
