02274nas a2200205   4500008004100000022001400041245012100055210006900176260000900245300000800254490000700262520153100269100002301800700002501823700002101848700003001869700001701899700002201916856013001938       2022                        eng d  a0039-788100aEnantioselective Cu(I)-catalyzed borylative cyclization of enone-tethered cyclohexadienones and mechanistic insights0 aEnantioselective CuIcatalyzed borylative cyclization of enonetet  cFEB   a8540 v133 a<p>Rapidly building molecular structures with both elements of complexity and flexibility is a key goal of organic synthesis. Here the authors show a tandem copper-catalyzed beta-borylation/Michael addition on prochiral enone-tethered 2,5-cyclohexadienones, to generate bicyclic borylated products in high yield and enantioselectivity. The catalytic asymmetric borylation of conjugated carbonyls followed by stereoselective intramolecular cascade cyclizations with in situ generated chiral enolates are extremely rare. Herein, we report the enantioselective Cu(I)-catalyzed beta-borylation/Michael addition on prochiral enone-tethered 2,5-cyclohexadienones. This asymmetric desymmetrization strategy has a broad range of substrate scope to generate densely functionalized bicyclic enones bearing four contiguous stereocenters with excellent yield, enantioselectivity, and diastereoselectivity. One-pot borylation/cyclization/oxidation via the sequential addition of sodium perborate reagent affords the corresponding alcohols without affecting yield and enantioselectivity. The synthetic potential of this reaction is explored through gram-scale reactions and further chemoselective transformations on products. DFT calculations explain the requirement of the base in an equimolar ratio in the reaction, as it leads to the formation of a lithium-enolate complex to undergo C-C bond formation via a chair-like transition state, with a barrier that is 22.5 kcal/mol more favourable than that of the copper-enolate complex.</p>
1 aJadhav, Sandip, B.1 aDash, Soumya, Ranjan1 aMaurya, Sundaram1 aNanubolu, Jagadeesh, Babu1 aVanka, Kumar1 aChegondi, Rambabu  uhttps://library.ncl.res.in/content/enantioselective-cui-catalyzed-borylative-cyclization-enone-tethered-cyclohexadienones-and