Bis(tosylimido)ruthenium(VI) porphyrins, [RuVI(Por)(NTs)2] (Por = TPP, TTP, 4-Cl-TPP, 4-MeO-TPP, OEP), were prepared in 60−74% yields by treatment of [RuII(Por)(CO)(MeOH)] with (N-(p-tolylsulfonyl)imino)phenyliodinane (PhINTs) in dichloromethane. In dichloromethane containing pyrazole, they reacted with alkenes or alkanes to give tosylamidoruthenium(IV) porphyrins, [RuIV(Por)(NHTs)(pz)], in about 75% yields. The reactions of [RuVI(TPP)(NTs)2] and [RuVI(OEP)(NTs)2] with styrene, para-substituted styrenes, norbornene, cyclooctene, and β-methylstyrene afforded the corresponding N-tosylaziridines in 66−85% yields. The aziridination of cis-stilbene and cis-β-methylstyrene by [RuVI(Por)(NTs)2] is nonstereospecific with a partial loss of the alkene stereochemistry. Kinetic studies on the reactions between [RuVI(TPP)(NTs)2] and 16 alkenes (cyclooctene, norbornene, 2,3-dimethyl-2-butene, styrene, para-substituted styrenes, α- and β-methylstyrene, and α- and β-deuteriostyrene) gave the second-order rate constants (k 2) ranging from (1.60 ± 0.06) × 10 - 3 to (90 ± 4) × 10 - 3 dm3 mol - 1 s - 1 at 298 K. The slope of the linear plot of log k 2 vs E 1/2 for eight representative alkenes was found to be −1.7 V - 1. In the case of para-substituted styrenes, linear correlation between log k R (k R = relative rate) and σ+ gives a ρ+ value as small as −1.1. However, the effect of para substituents on k R can be best accounted for by considering both the polar and spin delocalization effect. Measurements on the secondary deuterium isotope effect revealed that only the β-carbon atom of styrene experienced a significant change in its hybridization in reaching the transition state. All these are consistent with rate-determining formation of a carboradical intermediate. The reactions of [RuVI(TPP)(NTs)2] and [RuVI(OEP)(NTs)2] with adamantane, cyclohexene, ethylbenzene, and cumene resulted in tosylamidation of these hydrocarbons and afforded the corresponding amides in 52−88% yields. For cyclohexane and toluene, the tosylamidation products were formed in poor yields (ca. 10%). Kinetic studies on the reactions between [RuVI(TPP)(NTs)2] and nine hydrocarbons (cumene, ethylbenzene, cyclohexene, and para-substituted ethylbenzenes) gave the second-order rate constants (k 2) in the range of (0.330 ± 0.008) × 10-3 to (16.5 ± 0.3) × 10-3 dm3 mol-1 s-1. These reactions exhibit a large primary deuterium isotope effect, with a k H/k D ratio of 11 for the tosylamidation of ethylbenzene. In the case of para-substituted ethylbenzenes, both electron-donating and -withdrawing substituents moderately promote the reaction. There is an excellent linear correlation between log k R and a related carboradical parameter. On the basis of these observations, a mechanism involving the rate-limiting formation of a carboradical intermediate is postulated.

Metal-complex-catalyzed amidation of saturated CÀH bonds [1±7] is increasingly attractive as a CÀN bond-formation methodology. The nitrogen sources in most of these amidation reactions are iminoiodanes PhI¼NR, which are prepared from PhI(OAc) 2 and RNH 2 and are currently accessible for rather limited types of R groups (usually R ¼ ArSO 2 ). In very few cases can the PhI¼NR amidation procedure be applied to intramolecular amidation. [1b, 3c, 5] About two years ago, [4d] we found that PhI(OAc) 2 and RNH 2 (R ¼ p-MeC 6 H 4 SO 2 , p-NO 2 C 6 H 4 SO 2 ) could be used directly as the nitrogen source in intermolecular amidation processes. More interestingly, the ™PhI(OAc) 2 þRNH 2 ∫ amidation protocol is extendable to ™PhI(OAc) 2 þMeSO 2 NH 2 ∫ [4d,e,g] and ™PhI(OAc) 2 þCF 3 -CONH 2[4d] or PhCONH 2[4e]∫, in which cases the respective iminoiodanes are explosive or unknown. We envisioned that such a ™PhI(OAc) 2 þRNH 2 ∫ amidation procedure might be applicable to a wide variety of RNH 2 compounds and could be more readily extended to intramolecular amidation, as shown in Equation (1). Recent work by Du Bois and co-workers [7] excellently demonstrated that reactions of a series of carbamates (-OCONH 2 ) [7a] and sulfamate esters (-OSO 2 NH 2 ) [7b] with C X NH 2 H C X NH ML n (O) m (O) m + PhI(OAc) 2 (1)PhI(OAc) 2 , catalyzed by dirhodium complexes, afford oxazolidinones and cyclic sulfamidates, respectively, with high regioselectivity and good to excellent diastereoselectivity. These reactions occur by the direct intramolecular amidation of saturated CÀH bonds. Du Bois and co-workers found that these intramolecular amidation reactions are stereospecific, allowing synthesis of enantiomerically pure amidation products from enantiomerically pure carbamates or sulfamate esters. [7] However, it remains a challenge to realize asymmetric intramolecular amidation of saturated C À H bonds from prochiral RNH 2 substrates. Herein, we report the first metalloporphyrin-catalyzed intramolecular amidation reactions of saturated CÀH bonds that employ a ™PhI(OAc) 2 þRNH 2 ∫ procedure. The catalysts used are mainly the electron-deficient ruthenium porphyrin [Ru(tpfpp)(CO)] [8] (1, H 2 tpfpp ¼ meso-tetra(pentafluoro- Ar ArAr Ar

Carbonyl ruthenium(II) 5,10,15-tris(4-R-phenyl)-20-(4-hydroxyphenyl)porphyrins (R = Cl, Me) covalently attached to Merrifield's peptide resin were prepared. The catalyst with R = Cl was found to efficiently catalyze Cl2pyNO epoxidation of a wide variety of alkenes, including aromatic and aliphatic terminal alkenes, cis- and trans-stilbene, cyclohexene and cyclooctene, α , β-unsaturated ketones, conjugated enyne, glycal, and protected α-amino alkene. Unusual selectivities were observed for the epoxidations of 1,5-cyclooctadiene, cis-1-phenyl-3-penten-1-yne (9), 3,4,6-tri-O-acetyl-d-glucal (11), and 2-(Boc-amino)-1-phenylbut-3-ene (13), which feature a complete bisepoxide selectivity (1,5-cyclooctadiene), unprecedentedly high cis:trans ratio (9), and complete diastereoselectivity (11 and 13). The new heterogenized metalloporphyrin epoxidation catalysts are of high stability and reusability.

The total synthesis of racemic merrilactone A (a neurotrophic agent) is described, featuring simultaneous and stereospecific creation of the C4 and C5 stereocenters via a notable silyloxyfuran Nazarov cyclization. Full details of the successful synthetic strategy are given, as well as several examples of the interesting reactivity of intermediates that were prepared and studied during the execution of the total synthesis. A detailed investigation of the Lewis acid-catalyzed Nazarov cyclization of silyloxyfurans was conducted, including a systematic study of substrate scope and limitations. In addition, experiments were conducted that suggest the participation of Lewis acidic silicon species in the Nazarov cyclization.

A general reaction sequence is described that involves Nazarov cyclization followed by two sequential Wagner Meerwein migrations, to afford spirocyclic compounds from divinyl ketones in the presence of one equivalent of copper(II) complexes. A detailed investigation of this sequence is described including a study of substrate scope and limitations. It was found that after 4π electrocyclization, two different pathways are available to the oxyallyl cation intermediate: elimination of a proton can give the usual Nazarov cycloadduct, or ring contraction can give an alternative tertiary carbocation. After ring contraction, either [1,2]-hydride or carbon migration can occur, depending upon the substitution pattern of the substrate, to furnish spirocyclic products. The rearrangement pathway is favored over the elimination pathway when catalyst loading was high and the copper(II) counterion is noncoordinating. Several ligands were found to be effective for the reaction. Thus, the reaction sequence can be controlled by judicious choice of reaction conditions to allow selective generation of richly functionalized spirocycles. The three steps of the sequence are stereospecific: electrocyclization followed by two [1,2]-suprafacial Wagner-Meerwein shifts: the ring contraction and then an hydride, alkenyl or aryl shift. The method allows stereospecific installation of adjacent stereocenters or adjacent quaternary centers arrayed around a cyclopentenone ring.