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 in situ, 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-磺酰基环丙醇和锂化 1-磺酰基双环 [1.1.0] 丁烷的反应，开发了一种形成高应变 spiro[3.3]heptan-1-one 基序的新方法。在对原位形成的环丙酮进行初始亲核加成后，生成的 1-双环丁基环丙醇中间体在酸存在下容易发生“应变重定位”半频哪醇重排，直接提供取代的螺[3.3]庚烷-1-酮。当从取代的环丙酮等效物开始时，该过程显示出完全区域特异性和立体特异性，从而产生光学活性的 3-取代螺 [3.3] 庚烷-1-酮。该反应可能通过双环丁基部分的初始质子化，然后是所得环丙基羰基阳离子的 [1,2]- 重排进行。