01326nas a2200169   4500008004100000022001400041245007100055210006500126260000900191300001600200490000700216520076900223100002200992700002601014700002201040856009401062       2021                        eng d  a0022-326300aStereoselective total synthesis of (+/-)-pleurospiroketals A and B0 aStereoselective total synthesis of pleurospiroketals A and B  cOCT   a13572-135820 v863 aA full account of our efforts toward the stereoselective total synthesis of sesquiterpenoid-derived natural products (+/-)-pleurospiroketals A and B is described. Commercially available 3-methyl-2-cyclohexenone and 2,2-dimethyloxirane were used as key building blocks, and the substrate-controlled stereoselection was exploited to access the entire stereochemistry of these natural products. Initially, a planned synthetic route involving a [6,5]-bicyclic lactone intermediate was found to be insurmountable, and the later strategy comprising OsO4-NMO-mediated dihydroxylation of 3-methyl-2-cyclohexenone, followed by Luche reduction, Eschenmoser methylenation, and Bronsted acid-induced spiroketalization steps, was ultimately identified as the reliable strategy.1 aThorat, Sagar, S.1 aKrishna, Gamidi, Rama1 aKontham, Ravindar  uhttp://library.ncl.res.in/content/stereoselective-total-synthesis-pleurospiroketals-and-b02044nas a2200181   4500008004100000022001400041245016200055210006900217260000800286300001400294490000700308520132400315100002501639700002701664700002301691700002601714856012201740       2022                        eng d  a0022-326300aSolvent-driven mono- and bis-sulfenylation of (E)-beta-iodovinyl sulfones with thiols for flexible synthesis of 1,2-thiosulfonylalkenes and 1,2-dithioalkenes0 aSolventdriven mono and bissulfenylation of Ebetaiodovinyl sulfon  cMAR  a3934-39510 v873 a<p>
	The nature of solvent is a key factor for stereoselective mono-and bis-thiolation of (E)-beta-iodovinyl sulfones with thiols under basic conditions. A novel and unprecedented vicinal bisthiolation of (E)-beta-iodovinyl sulfones with thiols under the influence of K2CO3/DMSO at room temperature for quick assembly of (E)-1,2-dithio-1-alkenes is presented. Solvent-induced stereoselective monosulfenylation of (E)-beta-iodovinyl sulfones with thiols has also been established for the synthesis of both (E)- and (Z)-1,2-thiosulfonylethenes in MeCN and MeOH, respectively. Moreover, K2CO3-mediated desulfonylative-sulfenylation of (Z)-1,2-thiosulfonylethenes with thiols in DMSO furnished unsymmetrical (Z)-1,2-dithio-1-alkenes for the first time. The solvent-dependent versatile reactivity of (E)-beta-iodovinyl sulfones has been successfully explored to provide a set of (E)-/(Z)-1,2-dithio-1-alkenes and (E)-/(Z)-1,2-thiosulfonyl-1-alkenes in good to high yields with excellent stereoselectivities. Notably, this operationally simple process utilizes a broad substrate scope with good functional group tolerance and compatibility. The efficacy of the process has been proven for gram-scale reactions, and plausible mechanistic models are outlined on the basis of experimental results and control experiments.</p>
1 aReddy, Raju, Jannapu1 aKumari, Arram, Haritha1 aSharadha, Nunavath1 aKrishna, Gamidi, Rama  uhttp://library.ncl.res.in/content/solvent-driven-mono-and-bis-sulfenylation-e-beta-iodovinyl-sulfones-thiols-flexible01139nas a2200193   4500008004100000022001400041245015400055210006900209260000800278300001400286490000700300520040300307100002400710700001800734700002300752700002600775700001500801856012900816       2023                        eng d  a2052-412900aSynthesis of N-functionalized 2,3-disubstituted benzofurans/naphthofurans from para-quinone methides and isocyanides via the [4+1] annulation pathway0 aSynthesis of Nfunctionalized 23disubstituted benzofuransnaphthof  cJUL  a3746-37510 v103 a<p>
	A scandium triflate catalyzed [4 + 1] cycloaddition reaction of 2-hydroxy-substituted para-quinone methides and isocyanides has been developed. This operationally simple, efficient and practical protocol provides straightforward access to a variety of N-functionalized 2,3-disubstituted benzofuran/naphthofuran derivatives with broad functional group compatibility and good scalability.</p>
1 aKale, Someshwar, B.1 aKumar, Manish1 aShinde, Dinesh, R.1 aKrishna, Gamidi, Rama1 aDas, Utpal  uhttp://library.ncl.res.in/content/synthesis-n-functionalized-23-disubstituted-benzofuransnaphthofurans-para-quinone-methides