Palakodety Radha Krishna

Deprotonative metallation of ferrocenes using mixed lithium–zinc and lithium–cadmium combinations

A mixed lithium-cadmium amide and a combination of lithium and zinc amides were reacted with a range of ferrocenes; deprotonative mono- or dimetallation in general occurred chemoselectively at room temperature, as evidenced by subsequent quenching with iodine.

Mn(OAc)3—an efficient oxidant for regeneration of DDQ: deprotection of p-methoxy benzyl ethers

Abstract Mn(OAc) 3 has been successfully developed as a new oxidant for the regeneration of DDQ from HDDQ. This DDQ regeneration technique, making use of 3 equiv. of Mn(OAc) 3 –DDQ (10 mol%), was applied to the deprotection of p -methoxy benzyl (PMB) ethers.

Asymmetric Baylis-Hillman reaction using sugar acrylates-synthesis of optically active α-methylene-β-hydroxy alkanoates

Abstract A study on the asymmetric Baylis–Hillman reaction of three chiral acrylates; 1,2:5,6-di- O - iso -propylidine-α- d -glucofuranose-3-acrylate 1 , 2,3:5,6-di- O - iso -propylidine-α- d -mannofuranose-1-acrylate 2 and 1,2- O - iso -propylidine-5- O - tert -butyldimethylsilyl-α- d -xylofuranose-3-acrylate 3 , with various aldehydes was conducted, resulting in adducts with moderate diastereoselectivity (5–40% e.e.).

A simple and efficient PdCl2 mediated conversion of γ,δ-olefinic alcohols into C-glycosides

Abstract An efficient and mild intramolecular oxidative nucleophilic cyclisation protocol has been developed for the conversion of γ, δ-olefinic alcohols into the hemiketals, which in turn on deoxygenation led to the very important C-glycoside class of compounds.

Pd (OAc)2 mediated oxidative cyclisation of γ,δ - olefinic alcohols: A new route to C-vinyl furanosides

Abstract An intramolecular oxidative cyclisation protocol, making use of the Pd(OAc) 2 NaOAcO 2 system in DMSO, has been developed for the efficient conversion of sugar derived γ,δ -olefinic alcohols into the C-vinyl furanoside class of compounds.

The use of acetylenic aldehydes in Baylis–Hillman reactions: synthesis of versatile allyl propargyl alcohols ☆

Abstract The utility of acetylenic aldehydes in Baylis–Hillman reactions giving allyl propargyl alcohols in moderate to good yields is reported.

A facile zirconium(IV) chloride catalysed selective deprotection of t-butyldimethylsilyl (TBDMS) ethers

Abstract A simple and efficient protocol for the selective deprotection of t-butyldimethylsilyl (TBDMS) ethers using 20 mol% ZrCl4 in 20–45 min and in high yields, is reported, wherein it is demonstrated that acid and base sensitive groups and allylic and benzylic groups are unaffected.

Carbon — carbon linked disaccharides by de novo construction from furanyl sugar templates

Abstract The furanylated sugar units on de novo construction of a sugar moiety by oxidative unmasking of furan and introduction of three contiguous oxygenated carbon centers led to the incorporation of D and L-sugar units at the C-4 position of the furanoside, thereby leading to the synthesis of C(4) - C(5) linked disaccharides.

Catalytic FeCl3- or Yb(OTf)3-mediated synthesis of substituted tetrahydrofurans and C-aryl glycosides from 1,4-diols

Abstract A facile and mild protocol for the synthesis of substituted tetrahydrofurans, 2-deoxy C -aryl glycoside and C -aryl glycosides is described by use of 20 mol% FeCl 3 or Yb(OTf) 3 as acid catalysts. The benzylic carbocation generated undergoes intramolecular substitution by the oxygen nucleophile to result the tetrahydrofurans and C -aryl glycosides.

Pd(II)Cl2 mediated oxidative cycllsation of some 3-hydroxy 4-vinyl furanoside derivatives to synthetically valuable bis-furanosides

PdCl2 mediated oxidation of 3-hydroxy-4-vinylfuranosides (Ia-k) lead to the formation of aldehydes, some of them are ‘in situ’ trapped as their lactols (IIIa,c,e,f,h) and further converted to bis-furanoside lactones IVa,c,e,f,h).