Lithiation of 2-chloroglucal derivatives provides ready access to the corresponding 1-lithioglucals which undergo a variety of serve useful intermediates for further elaboration of the carbohydrate nucleus. Removal of the 2-chloro substituent may be affected using a Birch-type reduction. (c) 2006 Elsevier Ltd. All rights reserved.
Synthesis and stability of mixed nonfluorinated 1,1,1-trihalo-alkanes
作者:Cosme G. Francisco、Concepción C. González、Alan R. Kennedy、Nieves R. Paz、Ernesto Suárez
DOI:10.1016/j.tetlet.2005.10.118
日期:2006.1
1, 1, 1-Trihaloalkanes of the types R-CCl2I, R-CClBrI, and R-CBr2I belonging to 1,1,1-trihalo-1-deoxy-D-arabinitol series of alditols were prepared and fully characterized by anomeric alkoxyl radical fragmentation of the corresponding 2,2-dihalo-2-deoxy-D-arabino-hexopyranose derivatives. The analogous diiodohalo compounds R-CClI2 and R-CBrI2 could not be prepared by this methodology. The results strongly suggest that the stability of the mixed trihalo alditols decreases with increasing bulkiness of the halogen atoms. (c) 2005 Elsevier Ltd. All rights reserved.