Trimethylstannyl

The reaction of cyclohexene with the diazopyruvate 25 gives unexpectedly ethyl 3-cyclohexenyl malonate (26), involving Wolff rearrangement. No cyclo-propanation takes place[28]. 1,3-Dipolar cycloaddition takes place by the reaction of acrylonitrile with diazoacetate to afford the oxazole derivative 27[29]. Bis(trimethylstannyl)diazomethane (28) undergoes Pd(0)-catalyzed rearrangement to give the A -stannylcarbodiimide 29 under mild conditions[30]. 

Quinoline, 2,2,4-trimethyl-1,2-dihydro-antioxidant in polymers, 1, 395 Doebner-von Miller synthesis, 2, 468 Quinoline, trimethylstannyl-reactions, 2, 364 Quinoline, 4-vinyl-polymers, 1, 286... 

Stannanes also add across double bonds offiuonnated olefins in a free radical reaction Trimethylstannane undergoes stereospecific addition to hexafluorocyclo-butene to afford trans 1,2,3,3,4,4 hexafluoro 1 (trimethylstannyl)cyclobutane [5] (equation 1)... 

Halogen exchange with metallic derivatives provides a powerful means of introducing iodine into specific quinoline sites. It has proved possible to prepare 2-, 3-, and 4-iodoquinolines from the trimethylstannyl [82H(19)168] or lithium derivatives [86S670]. Protected 2-aminoquinoline, lithiated at C-3, was quenched with iodine to give a 90% yield of the 3-iodo derivative (86S670). 

Z,3R)- and (l ,35)- l-Methyl-3-(trimethylstannyl)-t-butenyl Diisopropylcarbamates via Lithiation Topical Procedure131 ... 

In a second set of examples, it was shown that the stereoselectivity of the aldehyde allylborations of 9-[( T)-l-trimethylsilyl- or l-trimethylstannyl-2-butenyl]-9-borabicyclo[3.3.1]nonane is controlled to a significant extent by conversion to an ate complex by treatment with butyllithium, MT-butyllithium or pyridine19. 

The reactions of 1-trimethylsilyl- or l-trimethylstannyl-2-butenyl-9-borabicyclo[3.3.1]-nonancs in the presence of pyridine are adequately explained by the usual transition structure 20 since the aldehyde should be capable of displacing pyridine as a ligand on boron. 

Trimethylstannyl)ethylidene]phosphoranes have been generated by conjugate addition of trimethylstannyllithium to triphenylvinylphosphonium bromide30 and, more efficiently, by deprotonation of the corresponding / -(trimethylstannyl)phosphonium salt31, and condensed with aldehydes and ketones. 

Methyl- C]thymine ([ C]FMAU) could be obtained in modest radiochemical yields via cross-coupling of [ CJmethyl iodide with l-(2 -deoxy-2 -fluoro-/3-D-arabinofuranosyl)-5-(trimethylstannyl)uracil. Optimal power was found to be 70W, since an increase to 100 W as well as a decrease to SOW resulted in lower radiochemical yields (Scheme 6). 

Recent review articles on the synthesis and use of N-(trimethylsilyl)imines [104] or N-(trimethylstannyl)imines [105] focus primarily on the preparation of / -lactams. 

The trimethylstannyl grouping in the phosphine (4) is replaced by diphenylphosphino upon reaction with chlorodiphenylphosphine. ... 

However, the reaction of (lZ,3Z)-l,4-dilithio-l,3-butadiene (36) with phenylantimony dichloride (Scheme 5) affords 1-phenylstibole (37),14 which has been converted to l.l -distibaferrocene (9).15 Unfortunately, there is no totally satisfactory synthetic route to dilithio compound 36. Sn/Li exchange of (lZ,3Z)-l,4-bis(trimethylstannyl)-l,3-butadiene (38) with methyllithium gives a good yield of 36, but the preparation of 38 is... 

Clive and coworkers have developed a new domino radical cyclization, by making use of a silicon radical as an intermediate to prepare silicon-containing bicyclic or polycyclic compounds such as 3-271 and 3-272 (Scheme 3.69) [109], After formation of the first radical 3-267 from 3-266, a 5-exo-dig cyclization takes place followed by an intramolecular 1,5-transfer of hydrogen from silicon to carbon, providing a silicon-centered radical 3-269 via 3-268. Once formed, this has the option to undergo another cyclization to afford the radical 3-270, which can yield a stable product either by a reductive interception with the present organotin hydride species to obtain compounds of type 3-271. On the other hand, when the terminal alkyne carries a trimethylstannyl group, expulsion of a trimethylstannyl radical takes place to afford vinyl silanes such as 3-272. 

As mentioned above the 1,1-organoboration reaction is reversible, and exchange is slow on the NMR timescale. This statement is in agreement with the chemical behavior of equilibrated mixtures of products. Thus, treatment of silicon borahomoadamantane derivative 92 with bis(trimethylstannyl)ethyne leads to the tin-containing compound 93 and liberation of bis(trimethylsilyl)ethyne (Scheme 44). With pyridine, the equilibrium is moved toward 1-boraadamantane completely due to the complexation <2001JOM(620)51>. 

The donor-free boratobenzene derivatives Mg(t 6-GsHsBMe)2 76 and Mg( 6-3,5-Me2C5H3BNMe2)2 77 were synthesized in good yields by the reactions of MgMe2 with the (trimethylstannyl)dihydroborinines... 

The synthetic pathway to TTeF (tetratellurafulvalene), starting from (Z)-1,2-fe(trimethylstannyl)ethane162 has been exploited for synthesising heteroleptic Pt complexes containing the only examples of the Te- and Se-analogs of edt2-.163... 

The reaction of silicon organophosphorus betaines with bis(trimethyl-stannyl)methylamine occurs similarly.84,96 Amidobetaine 65, which is most likely formed as an intermediate, decomposes to form silaneimine 66, which is trapped immediately by bis(trimethylstannyl)methylamine. When a twofold excess of organostannane was used, the yield of compound 67 was 90% (Scheme 29). 

Bromoalkynes also couple with vinylstannanes readily to result in enynes. Synthesis of protected enynals via cross-coupling of vinylstannanes with 1-bromoalkynes in the presence of a catalytic amount of Pd(II) has been reported (equation 143)252. Hiyama and coworkers extended the Stille methodology for sequential three-component coupling of trimethylstannyl(trimethylsilyl)acetylene with a vinyl iodide in the first step and cross-coupling of the intermediate trimethylsilylethyne with another alkenyl iodide in the presence of tris(diethylamino)sulphonium trimethyldifluorosilicate in the second step to generate a dienyne (equation 144)253. Both steps occur under palladium catalysis, in one-pot, to result in stereodefined l,5-dien-3-ynes. 

The foregoing stabilizing 1,3-diaxial interaction was shown to have potentially useful applications for stereochemical control of addition reactions56. The /l-trimethylstannyl cyclohexenone ketal 65 affords a nearly 1 1 mixture of isomeric c/s-diols 66 and 67 when hydroxylated with OsC>4 (equation 25). However, the chlorostannane 68 upon hydroxylation with OSO4, then Sn methylation, yields a 94 6 mixture favoring the a,a,-diol 66. Evidently, the conformational change induced by the 1,3-diaxial donor-acceptor... 

Thermolysis of the syn and anti /J-acetoxy stannanes, obtained by addition of Bu3SnLi to tram- or cis- 1,2-dimethyloxirane and subsequent acetylation, led to (Z)- or (E)-2-butene, respectively, by a stereospecific anti process (equation 34).73. It is postulated that a hyperconjugative interaction of the C—Sn bond facilitates departure of the acetate group in these acyclic systems. The trimethylstannyl and triphenylstannyl analogues likewise undergo anti elimination. 

FIGURE 14. trans-E isomer of the trimethylstannylpentadiene (R = H, 16) and the trimethylstannyl-hexadiene (R = Me, 17). Reproduced by permission of Freund Publishing House, Ltd., London, from Reference 95... 

The two trimethylstannyl groups are crystal- 210 lographically equivalent, however, the three methyl groups are rotationally and vibrationally different, as shown by INS spectroscopy at low temperature. 

---