Ethyl phosphorochloridite → Diethyl 2-[bis(3,5-di-t-butyl-4-methoxyphenyl)phosphino]phenylphosphonite

Participants

Reaction Steps

For example, referring to the reaction sequence shown below, 2-bromophenol (4) is reacted with trifluoromethanesulfonic anhydride to form 2-(trifluoromethanesulfonyl)oxy-bromobenzene (5), which is then reacted with bis(3,5-di-t-butyl-4-methoxyphenyl)phosphine oxide in the presence of a palladium complex catalyst to obtain bis(3,5-di-t-butyl-4-methoxyphenyl)(2-bromophenyl)phosphine oxide (6). Next, the compound (6) is reduced with trichlorosilane in the presence of N,N′-dimethylaniline to obtain bis(3,5-di-t-butyl-4-methoxyphenyl)(2-bromophenyl)phosphine (7). The compound (7) is reacted with diethyl chlorophosphonite in the presence of n-butyllithium to obtain diethyl 2-[bis(3,5-di-t-butyl-4-methoxyphenyl)phosphino]phenylphosphonite (8). Then, the compound (8) is reduced with lithium aluminum hydride in the presence of trimethylsilyl chloride to form 2-[bis(3,5-di-t-butyl-4-methoxyphenyl)phosphino]phenylphosphine (9). Thereafter, in the presence of n-butyllithium, the compound (9) is reacted with dimesylate of (2R,5R)-2,5-hexanediol, which is producible, for example, according to the method described in the literature (Tetrahedron: Asymmetry, 1991, 2, 569), whereby the aimed (S,S)-Me-UCAP-DTBM (3) can be produced in a high efficiency.

Provenance & Evidence