Dimetallations of 2-substituted furans and thiophenes: approaches to the 2, 3, 5-trisubstituted heterocycles

AJ Carpenter, DJ Chadwick

Index: Carpenter, Andrew J.; Chadwick, Derek J. Tetrahedron Letters, 1985 , vol. 26, # 43 p. 5335 - 5338

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Citation Number: 13

Abstract

Abstract The preparation and reactions of 3, 5-dilithiated furan and thiophene derivatives bearing the 4, 4-dimethyloxazolin-2-yl 2-substituent are reported. The 2-tert-butoxycarbonyl analogues cannot be prepared by direct dimetallation of the corresponding esters but sequential monometallation with in situ trapping by Me 3 SiCl ultimately affords the 3, 5- disilylated products: the 3-metallation of the 5-silylated intermediate is accelerated by LiCl.