SILYLPHOSPHINE - ALKENE REACTION ROUTES TO ACYCLIC AND CYCLIC ORGANOPHOSPHINES

Abstract

Radical reactions of Me3SiPH2, (Me3Si)2PH, Me2Si(PH2)2 and PH3 with selected alkenes have been examined as routes to new organo(silyl)phosphines. The Me3SiPH2/1,5-hexadiene reaction initiated by AIBN yields the phosphepane Me3SiP(CH2)6 (11a) and acyclic Me3SiP[(CH2)4CH=CH2]2 (12); the Me3SiPH2/1,3-butadiene reaction yields only acyclic butenyl phosphines Me3SiP(H)C4H7 (14a - C) and Me3SiP(C4H7)2 (15a - D). Reactions of Me3SiPH2 with P(CH=CH2)3 and MeSi(CH=CH2)3 yield the vinyl-substituted cis- and trans-phosphorinanes (CH2=CH)P(C2H4)2PSiMe3 (18a/18b) and Me(CH2=CH)Si(C2H4), PSiMe3 (20a/20b). (Me2Si)2PH/Me2Si(CH=CH2)2 reaction produces only the acyclic (CH2=CH)Me2SiC2H4P(SiMe3)2 (22) and Me2Si[C2H4P(SiMe3)2]2 (25). The Me2Si(PH2)2/1,4-pentadiene reaction yields phosphorinanyl derivatives Me2Si(PH2)[P(CH5] (27) and Me2Si[P(CH2)5]2 (28): no large-ring products form. The AIBN initiated reaction of CH2=CHCH2PH2 has been reinvestigated; the known bicyclic [(CH2)3]2P2 is obtained instead of the previously reported tricyclic [(CH2)3]3]3P2. The PH3/Me2Si(CH=CH2)2reaction yields mixtures of tentatively characterized Me2Si(C2H4)2PC2H4SiMe2(CH=CH2) (29) and [Me2Si(C2H4)2PC2H4]2SiMe2 (30). Solvolysis (with MeOH or H2O) of silylphosphines 11a, 27 (or 28), 12, 14a-C, 15a-D, 18a/18B, 20a/20B, 22 and 25 yields phosphorinanes (CH2)5PH (7) and Me2Si(C2H4)2PH (9), the new phosphepane (CH2)6PH (11b), HP[(CH2)4CH=CH2]2 (13, H2PC4H7 (16a-C), HP(C4H7)2 (17a-D), the cis- and trans-(CH2=CH)P(C2H4)2PH (19a/19b) and Me(CH2=CH)Si(C2H4)2PH (21a/21b), (CH2=CH)Me2SiC2H4P(H)SiMe3 (23), (CH2=CH)Me2SiC2H4PH2 (24) and Me2Si(C2H4PH2)2 (26). Attempts to obtain new tricyclic or large-ring cyclic phosphines by radical ring closure of 19a/19b and 21a/21b or cyclooligomerization of 23 or 24 were unsuccessful. New compounds are characterized by spectral (1H, 13C, and 31P NMR, MS and IR) data.