Sethuraman Sankararaman

Department Of Chemistry

K. Malola Narasimhan

V. Geetha Saraswathy

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Journal of Organic Chemistry

Highly concentrated solutions of lithium perchlorate in various organic solvents have been used as media for many synthetic transformation at room temperature which are otherwise difficult to carry out under ordinary conditions. The rates of several organic reactions are faster in these media compared than in pure solvents. More importantly high chemo-, regio- and stereoselectivities have been observed. The mild Lewis acidity of the lithium ion in donor solvents such as diethyl ether is responsible for these selectivities. Fine tuning of the Lewis acidity of the lithium ion, depending upon the solvent basicity and polarity, has been possible for selective activation of organic substrates in these media. The activation of carbonyl- and other oxygen-containing organic compounds in 5 M lithium perchlorate in diethyl ether (LPDE) and in nitromethane (LPNM) is presented.

European Journal of Organic Chemistry

Highly selective synthetic transformations catalyzed by lithium perchlorate in organic media

Epoxides from α,β-unsaturated ketones undergo highly chemo- and regioselective rearrangement to 1,3-dicarbonyl compounds in 5 mol dm-3 lithium perchlorate-diethyl ether medium by a 1,2-migration of the carbonyl group at ambient conditions. © The Royal Society of Chemistry 1999.

Fulltext

Journal of the Chemical Society - Perkin Transactions 1

Highly chemo- and regioselective rearrangement of α,β-epoxy ketones to 1,3-dicarbonyl compounds in 5 mol dm-3 lithium perchlorate-diethyl ether medium

Treatment of 3,4-dihydro-2H-pyran 1 with various alcohols 2 - 10 furnished the tetrahydropyranyl ethers 11 - 19 in the presence of 5M lithium perchlorate in diethyl ether (5M LPDE), which is essentially a neutral medium.

Tetrahedron Letters

Mild and efficient tetrahydropyranylation of alcohols-catalysis by lithium perchlorate in diethyl ether

The silyl enol ethers from cyclohexanone and cyclopentanone underwent efficient 1,4-addition to β-nitro- and β,β-dicyanostyrenes in 5 M lithium perchlorate/diethyl ether (LPDE) at ambient temperature to give the corresponding Michael adducts in good yields and with moderate stereoselectivity. The reaction was found to be highly chemoselective in that α,β-unsaturated carbonyl compounds failed to undergo Michael addition with the silyl enol ethers under identical conditions. The experimental evidence suggests that the mechanism involves transfer of the silyl group from the silyl enol ether to the Michael acceptor. The silyl enol ethers reacted with p-benzoquinone in 5 M LPDE to give benzofuran derivatives in good yields. Reaction with chloranil yielded the corresponding O-alkylated products while with DDQ, the corresponding C-alkylated products were obtained in excellent yields and with high regio- and stereoselectivities. © 1995, American Chemical Society. All rights reserved.

Chemoselectivity in the Michael Addition of Silyl Enol Ethers in Lithium Perchlorate-Diethyl Ether Medium. Evidence for Facile Silyl Group Transfer to Michael Acceptors

Aldehydes and acetals were very efficiently converted to acyclic and cyclic dithioacetals in 5 M lithium perchlorate/diethyl ether (LPDE) medium at ambient temperature in high yields. Spectroscopic and other experimental evidences strongly suggest the formation of oxocarbenium ion intermediates from acetals in 5 M LPDE which subsequently reacted with thiols to give the dithioacetals. Under the same conditions ketones and their acetals also reacted, albeit very slowly compared to aldehydes and acetals, to yield dithioacetals. The difference in their reactivity was successfully employed in the chemoselective dithioacetalization of aldehydes and acetals in the presence of ketones and their acetals. The chemoselective dithioacetalization of keto aldehydes has been realized with the keto group remaining intact. The present method offers a convenient, efficient, and neutral medium for the deprotection of acetals to aldehydes and also the chemoselective protection of aldehydes to dithioacetals. © 1994, American Chemical Society. All rights reserved.

Chemoselective Protection of Aldehydes as Dithioacetals in Lithium Perchlorate-Diethyl Ether Medium. Evidence for the Formation of Oxocarbenium Ion Intermediate from Acetals

The Journal of Organic Chemistry

Chemo- and Regioselective Isomerization of Epoxides to Carbonyl Compounds via Palladium Catalysis

Comprehensive Organic Synthesis

Acid-catalyzed Rearrangements of Epoxides

J. Chem. Soc., Chem. Commun.

Identification and synthesis of (Z)-(1′S,3′R,4′S)(–)-2-(3′,4′-epoxy-4′-methylcyclohexyl)-6-methylhepta-2,5-diene, the sex pheromone of the southern green stinkbug, Nezara viridula(L.)

Journal	Data powered by TypesetJournal of Organic Chemistry
Publisher	Data powered by TypesetAmerican Chemical Society
ISSN	00223263
Open Access	No