Methods of synthesizing phosphonic compounds and compounds thereof

A composition comprising a mixture of compounds comprising the formula IV and VII

• wherein R1, R2, R3 and R7 are hydrogen;
• and
• R4 comprises a higher alkyl group, a cycloalkyl group, a heterocycloalkyl group, a heteroaryl group, a protecting group, or an aryl group substituted with one or more SO2R or S(O)2OR groups, where R is hydrogen or an alkyl group.