Tetrahedron letters

Microwave-assisted synthesis of the Schöllkopf chiral auxiliaries:(3S)-and (3R)-3, 6-dihydro-2, 5-diethoxy-3-isopropyl-pyrazine

…, M Tullberg, Å Pilotti, P Ioannidis, K Luthman, M Grøtli

Index: Carlsson, Anna-Carin; Jam, Fariba; Tullberg, Marcus; Pilotti, Ake; Ioannidis, Panos; Luthman, Kristina; Grotli, Morten Tetrahedron Letters, 2006 , vol. 47, # 29 p. 5199 - 5201

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Citation Number: 24

Abstract

A practical and efficient methodology for the laboratory scale preparation of Schöllkopf's bis- lactim ether chiral auxiliaries (3S)-and (3R)-3, 6-dihydro-2, 5-diethoxy-3-isopropyl-pyrazine has been developed. The key step is the preparation of the 2, 5-diketopiperazine derivative by microwave-assisted heating in water. The protocol avoids reactions at low temperature and the use of high boiling solvents. Only inexpensive and readily available starting ...