Compoundsof the type RIEH react readily with CF3C=CCF3 togive R?EC(CF3)=C(CF3)H (E = N, P, As), and with CFIC-CH togive R?ECH=CHCF3 (E = N, As) and R?EC(CF,)= CH? (E = As). The isomer distribution of the products IS obta~ned from their n.m.r. soectra and the mechanism of the addition reaction is discussed.

The addition reaction R2EX + CF3C≡CCF3 → R2EC(CF3)=C(CF3)X has been investigated further (E = P and N); 1:1 adducts have been obtained from (C2H5)2PH, (CF3)2PH, (C6H5)2P—P(C6H5)2, and (CH3)2NCl, but not from (CH3)2PCl or (CH3)2P—P(CH3)2. (CF3)2PH also gives a 2:1 adduct. Triphenylphosphine causes the butyne to polymerize at − 78°. A similar but slower reaction takes place with trimethylamine. In the presence of water, trimethylamine and the butyne give the bis(butenyl) ether cis,trans (CF3CH=CCF3)2O as the major product.

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Diethylphosphine and methanethiol react with the cyclobutenes [Formula: see text](X = Cl, F) to give the compounds (C2H5)2 [Formula: see text] (Y = Cl, F) and [Formula: see text] (Y = F, Cl, C2H5). The disubstituted compound [Formula: see text] is also obtained from CH3SH and [Formula: see text].The related di(tertiary phosphine) (C6H5)2- [Formula: see text] can similarly be prepared. Methanethiol adds to [Formula: see text] to give the cyclobutane, but reacts with [Formula: see text]to give [Formula: see text]and with [Formula: see text] to give the cyclobutenone [Formula: see text]. Tetra-methyldiphosphine and [Formula: see text] yield the disubstituted compound [Formula: see text], whereas a cyclobutenone is obtained when (C6H5)2P—P(C6H5)2 reacts with [Formula: see text]. In some reactions, the phosphorane (C6H5)2PF3 is obtained, probably from (C6H5)2PF.

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