FACILE FORMATION OF 2-OXO-1,2-OXAPHOSPHORINANE FROM 1,4-DIHALO-2,3-DIMETHOXYBUTANE - A NEW PREPARATIVE ROUTE TO A 1-PHOSPHONO-PENTOPYRANOSE

Arbuzov reaction of 1,4-dibromo- or 1,4-diiodo-1,4-dideoxy-2,3-di-O-me thyl-L-threitol with diethyl phenyl phosphonite readily afforded 4,5-d imethoxy-2-oxo-2-phenyl-1,2-oxaphosphorinanes 7a (C-2(5)) and 7b (C-5( 2)), a 1-phosphonopentopyranose, via non-isolable ethyl 4-bromo-2,3-di methoxybutylphenylphosphinate precursors 6a,b.