TMANO

A combination of a metathesis and a Pauson-Khand reaction, which leads to tricyclic compounds starting from diene-ynes, has been described by Perez-Castells and colleagues [262]. Treatment of the Co-complex 6/3-86, obtained from the corresponding alkyne in 75 % yield, with 5 mol% of the Ru-catalyst 6/3-13 for 18 h, followed by addition of an N-oxide as trimethylamine-N-oxide (TMANO) or NMO as copromoters, gave 6/3-87 in 81% yield. 

Urine CKD Healthy subjects 30 patients 30 NMR LC-MRM MS 5-Oxoproline, glutamate, guanidoacetate, a-phenylacetylglutamine, taurine, citrate, and TMANO (43)... 

The l-propargyl-4-vinylazetidine derivative 374 undergoes Pauson-Khand cyclization at room temperature when reacted with cobalt octacarbonyl and trimethylamine /V-oxidc (TMANO) to give the tricyclic azetidine 375 (Equation 50). But when l-allyl-4-ethynylazetidine 376 is used, product 377 is obtained (Equation 51). In both cases, moderate yields with the formation of a single isomer of the products is achieved <1996TL6901, 1998JOC6786>. 

Pauson-Khand cyclization of vic-enyne derivatives of /3-lactams gave good yields of fused tricyclic compounds. The 1,4-disubstituted 2-azetidinone 391 and cobalt octacarbonyl gave the alkyne-cobalt carbonyl complex, which on thermolysis gave the tricycle 392 in 95% yield (Equation 54). When the complexes of 393 with cobalt octacarbonyl were treated with TMANO, a lower yield (65%) of 394 was obtained (Equation 55). A single diastereoisomer was formed in each case <1996TL6901>. 

The Pauson-Khand reaction has been used to obtain 4/5/5 systems from /3-lactams having unsaturated 3,4-substituents. Thus, the reaction of 443 with cobalt octacarbonyl in the presence of TMANO gave 444 in 80% yield C1996TL6901, 1998JOC6786>. 

The Pauson-Khand reaction provides a route to the 4/6/5 system from 3,4-disubstituted /3-lactams having both alkenyl and alkynyl groups, and will allow the presence of some functional groups on the substituents. The reaction of cobalt octacarbonyl and TMANO with 448 furnished 449 in 55% yield as a mixture of diastereoisomers in a ratio of 70 30 <1998JOC6786>. 

Complexation of propargyl aldehydes to cobalt also enhances the reactivity and enantioselectivity of the addition of alkylzinc reagents. This fact was used to create non-racemic enyne-ol 88 reacting the aldehyde 86 with bis-homoallylzinc in the presence of a chiral frzs-(sulfonamide) and Ti(OlPr)4. The resulting complexed substrate 87 underwent the PKR promoted by TMANO in a one pot fashion (Scheme 25) [122]. 

Finally, a Nicholas-type reaction is presumably responsible for an unexpected result reported by Alcaide. During their work devoted to the application of the PKR in the field of -lactams and azetidines they reacted complexed azetidine 91 with TMANO, isolating a mixture of the expected PK product 92 and by-product 93. The formation of 93 is believed to be a consequence of the ionization of the propargylic C - N bond at the cobalt-acycle step. The crowded metallacycle formed after the insertion of the olefin (93), would prompt the cleavage of the C - N bond, forming an ionic species (94) that would trap a hydride, possibly from a cobalt hydride giving 95, which then would follow the usual pathway towards the cyclopen-tenone (Scheme 27) [124],... 

AIBN = 2,2 -azobisisobutyronitrile 9-BBN = 9-borabicyclo [3.3.1]nonane Bn = benzyl BOC = f-butoxycarbonyl Bz = benzoyl CAN = ceric anunoninm nitrate Cp = cyclopenta-dienyl Cy = cyclohexyl DAST = diethylaminosnllur trifln-oride DBA = l,3-dibromo-5,5-dttnethylhydantoin DDQ = 2,3-dichloro-5,6-dicyano-l,4-benzoquinone DET = diethyl tartrate DIAD = diisopropyl acetylene dicarboxylate DIBAL-H = diisobutylalummum hydride DIPEA = diisopropyl ethyl amine DMDO = dimethyldioxirane HMPA = hexamethylphosphortriamide EDA = lithium diisopropy-lamide Ms = methylsulfonyl MOM = methoxymethyl NBS = iV-bromosuccmimide NMO = A-methylmorpholine iV-oxide PDC = pyridinium dichromate PMP = p-methoxyphenyl THP = tetrahydropyranyl TIPS = trisiso-propylsilyl TMANO = trimethylamine A-oxide TBDMS = t-butyldimethylsilyl Tf = trifluoromethanesulfonyl TMP = 2,2,6,6-tetramethylpiperidyl TMS = trimethylsilyl Ts = p-toluenesulfonyl. 

Diene iron tricarbonyl complexes are prepared by thermal or photochemical reaction of conjugated dienes with iron pen-tacarbonyl in the presence of TMANO, triiron dodecacarbonyl, ()]" -benzylidenacetone)iron tricarbonyl, diiron nonacarbonyl, or diiron nonacarbonyl absorbed on silica gel in the absence of solvent. The latter method is particnlarly usefiil for the preparation of complexes from polar electron-rich dienes and heterodienes. A reductive complexation of cycloheptatrienes using iron tricarbonyl and sodium borohydride to give cyclo-heptadiene iron tricarbonyl has been developed (Scheme 126). 

Oxidative removal of the iron tricarbonyl group can be achieved using iron trichloride, copper dichloride, CAN, hydrogen peroxide under basic conditions, 3-chloroperbenzoic acid, or TMANO. The latter oxidant is frequently the reagent of choice. Depending on the reagent, decomplexation may occur with or without concomitant transformation (Scheme 128). It is important to note that no racemization of optically active compounds is detected upon... 

Cyclobutadiene iron tricarbonyl complexes can be isolated and have been utilized in organic synthesis. Both intra- and intermolecular [2 + 2] cycloadditions of alkenes with cyclobutadiene complexes are observed upon decomplexation using CAN or TMANO (Schemes 164-165). The stereochemistry of the aUcene is retained in the product. Iron tricarbonyl diene complexes are compatible with metathesis reactions... 

Under some reaction conditions, cycloadditions without insertion of carbon monoxide have been observed. Reaction of complex (178) having an electron-deficient alkene under thermal conditions furnished the expected bicyclic enone (179) (Scheme 279). However, reaction promoted by TMANO gave cyclopentadiene (180). This... 

The conversion of (+)-8 to R-lf was accomplished through the intermediate fl-allyl species 9R (Scheme 4).,h The lf->3 conversion was carried out as is oudined in Scheme 1 to give 3R which produces the (IOR, 2 S) isomer R-lg in >98% de and (-)-(2/ )-butanol in >96% ee after trimethylamine W-oxide (TMANO) oxidation. Preliminary results have also been obtained for 2,3-dihydrofuran (84% de), c -2-butene (>85% defrom 95 5 c/t mixture),... 

A novel synthetic approach was developed by R.E. Taylor et al. for the preparation of the triene portion of the biologically active polyketide apoptolidin. The allylic chloride substrate was prepared from an allylic alcohol via a thionyl chloride mediated rearrangement. Next, the allylic chloride was subjected to the Ganem oxidation by treating it with five equivalents of trimethylamine A/-oxide (TMANO) in DMSO at room temperature to obtain the desired a,p-unsaturated aldehyde. Interestingly, the original Kornblum oxidation conditions were not well suited for this system because of the required high reaction temperature. 

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