We next investigated alternate oxidation approaches, in particular borylation-oxidation. Although the desymmetrization of 1,4-dienones via borylation is not known, there are examples of asymmetric borylation on both acyclic and cyclic enones. As mentioned previously, while the dienone substrate appeared to be unreactive under most epoxidation conditions, borylation of dienone 28a under Kobayashi's borylation conditions gave the desired product in racemic form. Translation of these conditions to the asymmetric version proved challenging wherein Kobayashi's bipy-derived ligand failed to deliver any appreciable yields of the desired borylated compound 29; however, a survey of various BOX ligands led to the discovery that the commercially available (R,R)-i Pr-Pybox L1 readily desymmetrized the molecule in excellent enantioselectivity albeit in low yields. Furthermore, there seemed to be a delicate balance between conversion and enantioselectivity at the 4-hydroxy position, wherein the judicious choice of a TES protecting group proved optimal for both ee and overall yield (Figure , table ). After further optimization, this symmetry-breaking borylation-oxidation sequence could be performed on 50 mmol scale with 75% yield and 94% ee over 3 steps (see SI for full details). Importantly, the use of L1 in process chemistry is precedented. With enantiopure diol 30 in hand, attention turned towards installing the requisite alkyne and internal olefin found in enyne 22. Conjugate addition of the resulting dihydroxyenone 30 occurred with complete diastereoselective control to deliver ketone 31 in excellent yield. It is worth noting that the chelation-controlled alkynylation proved highly chemoselective even at ambient temperature. NaBH4 reduction of 31 proceeded with high trans selectivity (d.r. = >20:1, relative stereochemistry confirmed via nOE), followed by selective bis-TBS protection of triol 32 to deliver tertiary alcohol 33. It was anticipated the elimination of alcohol 33 would prove challenging due to its inaccessibility, however after various attempts (see the SI), the use of SOCl2 in pyridine/DCM smoothly provided the desired enyne 22 after TMS deprotection.