Benzylidene Acetal Fragmentation Route to 6-Deoxy Sugars: Direct Reductive Cleavage in the Presence of Ether Protecting Groups, Permitting the Efficient, Highly Stereocontrolled Synthesis of β-D-Rhamnosides from D-Mannosyl Glycosyl Donors. Total Synthesis of α-D-Gal-(1→3)-α-D-Rha-(1→3)-β-D-Rha- (1→4)-β-D-Glu-OMe, the Repeating Unit of the Antigenic Lipopolysaccharide from Escherichia hermannii ATCC 33650 and 33652.