Kantam, M Lakshmi

Kavita, B

Rahman, Ateeq

Sateesh, M

NOPR

Indian Journal of ChemistryVol. 37B, October 1998, pp. 1039 - 1040MgAICOrHT catalyzed ring opening ofoxiranes with TMSN3M Lakshmi Kantam", B Kavita, Ateeq RahmanS;M SateeshIndian Institute of Chemical Technology,Hyderabad 500 007, IndiaReceived 16 October 1997; accepted 26 February 1998MgAIC03-HT is an effective catalyst for the nu-cleophilic ring opening of oxiranes with TMSN3•Azidosilyl ethers and cyanohydrin trimethylsilyl-ethers are industrially important organic interme- !diates in the synthesis of cyanohydrins, l3-aminoalcohols, a-amino acids and other biologically im-portant compounds':", Substantial progress hasbeen made recently in the development of catalyticmethods for the synthesis of cyanohydrintrimethylsilylethers and azidosilylethers by the iring opening epoxides .. It is generally performedusing various homogeneous Lewis acid catalystssuch as Zn1/, LaCI/, AICI3, KCN-l8-Crown-6 or '"Bu4N+CN- (ref. 5) etc. Current interest is focused'on the replacement of toxic, corrosive Lewis acidsby environmentally friendly solid acids and basessuch as zeolites", clays', etc. for nucleophilic addi-tion and in other Friedel-Crafts.reactions, Onaka etal.8 reported strongly acidic clay montmorillonite(Fe-Mont) and non-acidic CaF2 and hydroxyapatiteare efficient solid catalysts for cyanosilylation ofcarbonyl compounds with cyanotrimethylsilane,Besides providing operational simplicity andhigher selectivity with the scope for reusability,these solid catalysts have shown synergistic reac-tion promoting effect due to the presence of bothacid and basic sites on the surface of solid. Re-cently, a few reports have appeared on the utilitiesof mixed metal oxides obtained from hydrotalcitesprecursors for various organic transformations inliquid phase reactions" and on the nucleophilic ringopening of oxiranes using TMSCN by MgAIC03-HT'o. The calcination of mineral hydrotalcite"Mg6AI(OH),6C03.4H20(HT) which belongs to theNoteS,NoTable I--Ring opening of oxiranesOxirane Nucleophlle Catlilyst Product Isolate<lYlelds(%)00 TMSN:l A O::'Me3 6200 OOSIMe3TMSN:l B ' ~O-N:l00 ONHPhPhNH:1 A 61OH0° PhNH2 B O:h 55~~o,~.'TMSN:l A() \N362<:»~TMSN3 B ©f::-' 63~ ~PhNH2 A () 50<:>~PhNH2 B~50Qp TMSN3 A aSIMe3 55N3:)0 M:rOSlMe3TMSN3 A 52M N3235678Q10A) MgAICOJ-HT: B) lnAlCOJ-HTanionic clay family gives solid solutions of bimet-allic oxides of the composition Mg6AI20s(OH)2'Thus, the calcined hydrotalcites presents a uniqueclass of heterogeneous catalysts which have pro-nounced but controlled basic character.We herein report the use of calcined MgAIC03-HT as an efficient catalyst for the nucleophilic ringopening of oxiranes with trimethylsilyl azide andaniline giving good yields of the products(Table I). ZnAIC03-HT was also tested for thesereactions. Trimethylsilyl azide and aniline gavetrans-2-anilinocyclohexanol and trans-l-azido-1040 INDIAN J CHEM, SEC.B,OCTOBER 19982-trimethylsilyloxy)cyclohexane, respectively.Similarly, trans products were obtained from cy-clopentene oxide and cis-2, 3-dimethyloxirane.Although Yamashita et al.12reported the asymmet-ric catalytic ring opening of oxiranes with TMSN3by metal (II) tartrates, our investigations on thenucleophilic ring opening of oxiranes withMgAIC03-HT in the presence of (+)-DET resultedin poor enantioselectivities (1-3%). The reaction isfast and very mild. The recovered catalyst revealsalmost similar catalytic activity without deactiva-tion. The advantages of the catalysts are stability toair, moisture and the easy recovery from the reac-tion mixture simply by filtration.Experimental SectionPreparation of MgAIC03.HT. The MgAIC03-HT was obtained by the procedure reported byReichle et al.13.The catalyst was calcined at 723 Kfor 4 hr.General procedure for ring opening of epox-ides. A 100 mL two necked round bottomed flaskequipped with a magnetic stirring bar was chargedwith calcined MgAIC03-HT (0.200 g), the sub-strate (2 mmoles) in dry benzene under N2 atmos-phere. Trimethylsilylazide (2 mmoles) was thenadded to the reaction mixture and the contents al-lowed to stir at room temperature. The reactionwas monitored by TLC. After completion of thereaction, the catalyst was filtered and the filtratewas column separated on silica gel (Hexane:EtOAc). The products were analyzed by IH NMRand IR spectra.AcknowledgementWe thank DST, UGC and IFCPAR respectivelyfor providing financial support to M Sateesh, BKavita and Ateeq Rahman.References1 Kruse G C, in Chirality in Industry, edited by A N Collins,G N Sheldrake & J Crosby (Wiley, Chichester), 1992, ch.14.2 Luis E Martinez, Nugent W A & Jacobsen E N, J OrgChern,61, 1996,7963.3 Evans D A, Truesdala L K & Caroll G L, J chem SocChernCommun, 1973,55.4 Vougioukas A E & Kagan H B, Tetrahedron Left, 28,1987,5513.5 Evans D A & Truesdala L K, Tetrahedron Left, 1973,4929.6 Onaka M, Sugita K & Izumi Y, J Org Chern, 54, 1989,1116.7 Choudary B M, Lakshmi Kantam M, Sateesh M, Kotes-wara Rao K & Lakshmi Santhi P, Appl Catal A General,149,1996,257.8 Onaka M, Higuchi K, Sugita K & Izumi Y, Chern Left,1989, 1393.9 Choudary B M, Narender N & Bhuma V, Synlett, 1994,641.10 Choudary B M, Narender N & Bhuma V, Synth Commun,25,1995,2829.II Cavani F, Trifiro F & Maccari A, Catalysis Today, II,1991,173.12 Yamashita H, Bull ChernSocJpn, 61, 1988, 12\3.13 Reichle W T, J Catal, 94, 1985,547.

MgAICO3-HT catalyzed ring opening of oxiranes with TMSN3

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MgAICO3-HT catalyzed ring opening of oxiranes with TMSN3

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