Patent ID: 7683186

Claim:
A phosphorus compound defined by the following general formula (1): in the formula (1), R 1 denotes a hydrogen atom or a hydroxy protective group; R 2 denotes a group defined by the following formula (R 2 -1) or (R 2 -2); R 3 , R 4 , R 5 , and R 6 may be the same or different and independently denote a hydrogen atom, an alkyl group, an alkoxy group, an acyloxy group, a halogen atom, a haloalkyl group, or a dialkylamino group; two among R 3 , R 4 , R 5 , and R 6 may form an aromatic ring optionally having a substituent group, and two among R 3 , R 4 , R 5 , and R 6 may form a methylene chain optionally having a substituent group or a (poly)methylenedioxy group optionally having a substituent group: in the formula (R 2 -1) and (R 2 -2), R 7 denotes an alkyl group, a cycloalkyl group, an aryl group, an alkoxy group, or an aryloxy group; R 8 and R 9 independently denote a hydrogen atom, an alkyl group, or an aryl group; z denotes a divalent group selected from an oxygen atom, a sulfur atom, NR N and Si(R Si ) 2 , R N denoting an alkyl, an aryl, an alkanesulfonyl, an arylsulfonyl, or an acyl group and R Si denoting an alkyl or an aryl group or Si(R Si ) 2 may form a ring; and (a) denotes an integer of 0 or 1.