Primary and secondary alkyl chlorides have been conveniently prepared by the reaction of tri-noctylphosphine with carbon tetrachloride solutions of the corresponding alcohols. This rapid, high yield reaction proceeds with inversion of configuration. By using carbon tetrabromide the method has been extended to the synthesis of alkyl bromides.Canadian Journal of Chemistry, 46, 86 (1968) The formation of ylid 1 (R = C6H5) and trivhenvlvhosvhine dihalide (2) from the inter-[41aciion o i trip~ienylphosphine with carbon tetra-Accordingly, we have found that phosphines halides (eq. [l]) was simultaneously and inde-snloothly convert alcohols to chlorides (eq.[5]). pendently discovered by Rabinowitz and Marcus (1) and Ramirez and co-workers (2). An ionic mechanism iilvolving nucleophilic displacement on halogen has been invoked (3) to account for the formation of these products (eqs.[2] and [3]).Ylids of structure 1 (R = C6Hj) possess considerable syntlietic potential since they provide a route to otherwise difficultly accessible 1,l-dihaloalkenes on reaction with carbonyl compounds (1,2,4). Reagents of the type R3PX2 (R = C6H5 or 12-C4H9) have been demonstrated to perinit the conversion of alcol~ols to alkyl halides to proceed generally without complication of elii1liilation or rearrangement (5, 6); in addition, they convert phenols to aryl ha!ides (6,7) without formation of position isomers.The present study arose out of a consideration that intermediates of structure 3 (or 4) C O L I~~ be trapped by reaction with alcohols to provide 5 (or 6), e.g.The anticipated collapse of 6 to alkyl halide and tertiary phosphine oxide finds ample analogy in a related study (8).[5] R3P + R'OH + CCI4 + R'C1 + R 3 P 0 + HCC13 where R = t1-C8Hl7 or C6H5Using tri-12-octylphosphine (TOP) and primary alcohols, conversions are of the order 90-100 % in favorable cases. Tripl~enylphospl~ine may also be used at longer reaction times.1 Although no attempts at optin~ization have been made, we find that this facile transformation is conveniently accomplished (for chlorides) by adding a slight excess over one inole equivalent of TOP to a solution of alcohol in carbon tetracl~loride as solvent. A vigorous reaction ensues which is con~plete, in the case of primary alcohols, in ca. 5 min. The product is readily isolated by standard methods of distillation and chromatograpl~y (cf. Experimental).Typical results are the formation of i2-C5H1 lC1 (94%), C6H5CH2CI (loo%), rz-C8HI7Cl (93 %), and C6H5CH2CH2C1 (66 %).2 Secondary alcohols also react. Thus, after ca. 5 mill reaction time, sec-butyl chloride and 2-chlorooctane were formed in 60 % and 80 % yields,

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than that observed* with the 11,15-bistetrahydropyranyl ether of prostaglandin Fia (4).

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10) Analogous proposals have appeared to account for the reactions of trialkylboranes with ylides1 and carbanions.2 See also ref 3.