Some Syntheses of Optically Active Phosphorus Compounds

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I.R. and N.M.R. spectra, specltlc rotations, and elemental analysesof the products .... noted that the signs of specific rotation for the organophosphorus pro- ducts ...
PHYSICAL SCIENCES

121

Some Syntheses of Optically Active Phosphorus Compoundsl K. DARRELL BERLIN and DONALD B. BURPO' Department 01 Chemistry, Oklahoma State Unlvenlty, Stillwater The synthesis of optically active phosphorus compounds for the most part has been limited to those chemicals which contain an asymmetric phosphorus atom. Those compounds which do not contain an asymmetric phosphorus atom include (-)-menthyl- and (-)-bomyl P, P-diethyl 2phosphonopropionate (Tomoskozi, 1966) and (- ) -menthyl dlphenylphosphinate (Lewis, Korpiun and Mislow, 1967). The latter was not well characterized In the report of Lewis, Korplun and Mislow ( 1967). Several optically active organophosphorus compounds were synthesized which do not contain an asymmetric phosphorus atom. Condensations of diphenylphosphlnyl chloride (1) with either an amine, an alcohol, or a sodium alkoxide were Investigated. The reactions Involve formation ot a P-N or P.-O bond via nucleophilic displacement on phosphorus by an oxygen or IUtrogen atom. of

Two equivalents of optically active primary ainltie pet one equivalent 1 were utilized in the synthesis of three amides ot dlphenylpho8phlDlc

·w.

aratefal17 aclulO.led.. partial ,apport by the Bet.reh PouDclatwa, Oklahoma St 3te UDfvehit)". 'Predoetoral CaDdiciate 1911·18.

PROC. OJ' '1'HIi OKLA. ACAD. OF SCI. FOR 1967

122

acid. TIle 80dlum aJkoxI_ at (-) -menthol and (-) -bomeol were prepared IIDce

2IU'fHs

+

+

+

(c.B.).P(O)CI -+ RN'HP(O) (C.u.>s RNH" C1 1 e.tmtleaUon at the alcohol with 1 wu dlfflcult. Triethylamine was UBed ROB Na -+ RONa O.6H,

+

+

+

U

aD

+

RONa 1 -+ ROP(O) (c.u.), NaCl add 8C&venger In the eater Iynthesis from (-) -2-methyl-1-butanol

and 1.

ROB

+ 1+

(CH,CHs)~ -+

ROP(O) (CeH,),

+

(CH,CH,),NH, C1

Durtna' addJtJon of 1 to an optically active amine In ether, the amide

and hydrochloride ot the amine began to precipitate. In the workup of the reaction mixture, the IOlid precipitate was washed with water to dis80Jve the Ionic .salt. The residue was then recrystalllzed to give pure amide. After reaction of 1 with an alkoxlde, the slight excess of 1 was removed by extraction with aqueous sodium bicarbonate. Steam c:Ustillatlon proved Wleful u a means for removing the unreacted (- ) -menthol or ( - ) ·bomeol. The hydrochloride of triethylamine was separated from the reactlon mixture by ttJtratJon. Then the excess (-) -2-methyl-l-butanol and triethylamlne were removed from the ester by evaporation using high vac-

uum.

The optically active products were as tollows: