01546nas a2200217   4500008004100000022001400041245009100055210006900146260007500215300001400290520072600304653002501030653003401055653001601089653001501105653002101120100002401141700001901165700001901184856012501203       2016                        eng d  a1434-193X00aEnantioselective modular total synthesis of macrolides Sch725674 and C-4-epi-Sch7256740 aEnantioselective modular total synthesis of macrolides Sch725674  aPOSTFACH 101161, 69451 WEINHEIM, GERMANYbWILEY-V C H VERLAG GMBHcFEB  a1215-12263 a<p>The convergent total synthesis of Sch725674 has been accomplished by starting from (R)-1,2-epoxyheptane and assembling five modules in a highly stereoselective manner to give the final product in 6.6% overall yield. The same strategy was extended to the synthesis of its C-4 epimer. Key reactions of the synthetic pathway include a Jacobsen hydrolytic kinetic resolution of an epoxide followed by its regioselective opening through a Yamaguchi-Hirao alkynylation, and ring-closing metathesis reaction to furnish the unique 14-membered ring macrolactone. In addition, the influence of protecting groups on the efficiency of the ring-closing metathesis (RCM) macrocyclization has been studied to maximize its yields.</p>10aAsymmetric synthesis10aHydrolytic kinetic resolution10aMacrocycles10aMetathesis10aNatural products1 aSharma, Brijesh, M.1 aGontala, Arjun1 aKumar, Pradeep  uhttps://library.ncl.res.in/content/enantioselective-modular-total-synthesis-macrolides-sch725674-and-c-4-epi-sch725674-001257nas a2200241   4500008004100000022001400041245015100055210006900206260007500275300001000350490000600360520034400366653001400710653001300724653002100737653002800758653001100786100002300797700001900820700002400839700002200863856013000885       2016                        eng d  a2193-580700aN-heterocyclic-carbene-catalyzed regioselective oxidative ring-opening of epoxides with aromatic aldehydes: a facile entry to alpha-acyloxyketones0 aNheterocycliccarbenecatalyzed regioselective oxidative ringopeni  aPOSTFACH 101161, 69451 WEINHEIM, GERMANYbWILEY-V C H VERLAG GMBHcJAN  a48-510 v53 a<p>A high-yielding synthesis of -acyloxyketones using a N-heterocyclic-carbene (NHC)-catalyzed, oxidative ring-opening of epoxides with aromatic aldehydes is described. This regioselective, oxidative process utilizes a N-bromosuccinimide (NBS)/DMSO combination as the oxidant system and Et3N as the base under mild reaction conditions.</p>10aaldehydes10aepoxides10ahalogen oxidants10aN-heterocyclic carbenes10aoxygen1 aReddi, Rambabu, N.1 aGontala, Arjun1 aPrasad, Pragati, K.1 aSudalai, Arumugam  uhttps://library.ncl.res.in/content/n-heterocyclic-carbene-catalyzed-regioselective-oxidative-ring-opening-epoxides-aromatic-0