In the ini al stages of our project, we op mized and scaled up the original Camps' procedure to obtain the key intermediate 2 from commercially available diketone 3 22 . Treatment of 3 with TMSCN catalyzed by ZnI2 in CHCl3 afforded the silylated cyanohydrin 4 as a mixture of diastereomers in near quan ta ve yield. Subsequent treatment of 4 with POCl3 in pyridine led to a regioisomeric mixture of bicyclic unsaturated nitrile 5, which was then subjected to cataly c hydrogena on, yielding dinitrile 6 as the sole endo,endodiastereomer, as determined by Camps' seminal synthesis. Notably, the addi on of TEA did not result in the reduc on of nitriles compared to the TEA-free method. The acidic hydrolysis of the nitrile furnished diacid 7 endo,endo without any loss of diastereomeric purity. The structure of this compound was unambiguously confirmed by X-ray diffrac on (XRD) analysis (see SI for details). We successfully scaled up the abovemen oned steps to obtain diacid 7 endo,endo in a single synthe c run, yielding over 100 g (Scheme 1). Subsequently, diacid 7 endo,endo was readily converted to the corresponding methyl ester 2 endo,endo through treatment with SOCl2 in MeOH, preserving its stereochemistry. Surprisingly, the applica on of Camps' protocol (treatment of the diester 2 with LDA in THF at -78 o C, addi on of I2 at -78 o C, warming to room temperature, and quenching with aqueous NH4Cl) for the assembly of the stellane core using diester 2 endo,endo did not yield the desired compound 1, even in trace amounts. In our case, the epimeric mixture of diastereomers 2 was recovered in approximately 80% yield. Such an epimeriza on led us to assume the possibility of any reac ons occurred at -78 o C, which could not be detected at room temperature. To prove this, we inves gated the reac on using NH4Cl as the quenching agent at -78 o C, which resulted in the intramolecular Claisen condensa on to ketoester 8, whose structure was confirmed by XRD (see SI for details). We also found that the yield of 8 depends on the quenching temperature. Increased temperatures significantly lowered the yield of 8 primarily giving the epimeric mixture of diester 2 as a result of retro-Claisen reac on of 8 (as shown separately, Scheme 1, bo om right). The prepara ve procedure for the synthesis of compound 8 was elaborated without the addi on of I2 to the reac on mixture and scaled-up to 20+ grams as this ketone also is seen as a precursor for o-benzene mimics.