Diphenylphoshinoylethyne reacts with diols under basic conditions to produce cycloacetalic phosphine oxides. The reaction appears to be general and particularly effective with carbohydrate derivatives. The 2-(diphenylphoshinoyl) ethylidene (DPE) acetals produced are stable in acidic media while they can be cleaved under reductive and/or basic conditions: base-catalyzed transacetalization is a method of choice for their mild and ...