| Phosphorinanes containing silicon and phosphorus in the ring (19, 21, 22, 23, 30) have been prepared using AIBN-initiated.;(DIAGRAM, TABLE OR GRAPHIC OMITTED...PLEASE SEE DAI).;Addition of the PH(,2) unit of (CH(,3))(,3)SiPH(,2) to (CH(,3))(,2)Si(CHCH(,2))(,2), CH(,3)Si(CHCH(,2))(,3) and Si(CHCH(,2))(,4) yields the 4-silaphosphorinanes (19, R = R' = CH(,3); 21, R = CH(,3), R' = CHCH(,2); 22, R = R' = CHCH(,2); 23) selectively. 21 is formed as a 1:1 cis:trans isomer mix- ture. The reaction proceeds through an acyclic intermediate which undergoes intramolecular cyclization rather than polymerization. In addition to phosphorinanes, 5-10% of five-membered ring products have been tentatively characterized. 19, 21, 22, and 23 can be quantitatively solvolyzed with CH(,3)OH or H(,2)O to the secondary phos- phine heterocycles, 24, 27, 28 and 29, respectively. Compound 24 can be further derivatized to the phosphine oxide, (CH(,3))(,2)Si(CH(,2)- CH(,2))(,2)P(O)H (25) and 19 to the phosphinic acid, (CH(,3))(,2)Si(CH(,2)CH(,2))(,2)- P(O)OH (26). Reaction of PH(,3) with (CH(,3))(,2)Si(CHCH(,2))(,2) does not yield the expected 24 but, rather, an oligomeric product (20).;Products were characterized by ('1)H, ('13)C, and ('31)P nmr, infrared and mass spectroscopic data, and elemental analytical analysis. Karplus correlations and variable-temperature nmr of 24 were used to determine conformational preference of the P-H proton in 24, 27, 28 and 29.;addition AIBN = 2,2'-azobis-(isobutyronitrile) of (CH(,3))(,3)SiPH(,2) to vinyl-substituted phosphines and silanes.;Addition of (CH(,3))(,3)SiPH(,2) to (C(,2)H(,5))(,2)NP(CHCH(,2))(,2) affords the novel 30 as one isomer. 30 has reactive P-X bonds of opposite polarity at each phosphorus (ie. X-P = (delta)('-)-(delta)('+); P-X' = (delta)('-)-(delta)('+)). The opposite polarity feature of the phosphorus atoms in 30 is observed in reactions with CH(,3)OH, where the P-Si bond is readily cleaved with one equivalent of CH(,3)OH to give (C(,2)H(,5))(,2)NP(CH(,2)CH(,2))(,2)PH (32). Phosphorus-nitrogen bond cleavage occurs subsequently to form CH(,3)OP(CH(,2)CH(,2))(,2)PH (33). 32 eliminates (C(,2)H(,5))(,2)NH at 150(DEGREES)C to give polymeric - P(CH(,2)CH(,2))(,2)P (,n)- (34).;The syntheses performed herein were conducted to provide a general methodology for the preparation of phosphorus heterocycles and were designed to take advantage of the difunctionality (ie. P-H and P-Si) of the silylphosphine reagent. The hitherto unknown 4-silaphosphorinane and difunctional 1,4-diphosphacylohexane ring systems have been prepared. These compounds have additional sites of reactivity which may make them useful as synthons in complex molecule synthesis. |
