Despite the extensive mechanis c inves ga ons, the primary objec ve of this project was to develop an effec ve protocol for the synthesis of stellane 1,5-dicarboxylic acid (Scheme 5). Summarizing all the obtained data, the process was designed as follows: star ng from the commercially available diketone 3, a dinitrile 6 endo,endo was synthesized in three steps with a total yield of 60% on a 100 g scale from a single synthe c run. Subsequently, the dinitrile was subjected to base-mediated hydrolysis, resul ng in a mixture of diastereomers of diacid 7 in a ra o of exo,endo : endo,endo : exo,exo = 4 : 2 : 1. This mixture was then converted to the corresponding diester 2 while maintaining the diastereomer ra In this mixture, both the exo,exo and exo,endo diastereomers have the poten al to yield the desired stellane 1. Therefore, the mixture was directly used in further lithia on/I2-mediated oxida on without the for preliminary separa on of diastereomers. The target product 1 was obtained on a 50 g scale with a yield of 65%.