Tosylamidations allylic/benzylic

As shown in the manganese- and ruthenium-catalyzed intermolecular nitrene insertions, most of these results supposed the transfer of a nitrene group from iminoiodanes of formula PhI=NR to substrates that contain a somewhat activated carbon-hydrogen bond (Scheme 14). Allylic or benzylic C-H bonds, C-H bonds a to oxygen, and very recently, Q spz)-Y bonds of heterocycles have been the preferred reaction sites for the above catalytic systems, whereas very few examples of the tosylamidation of unactivated C-H bonds have been reported to date. 

Gyclization/hydrosilylation of enynes catalyzed by rhodium carbonyl complexes tolerated a number of functional groups, including acetate esters, benzyl ethers, acetals, tosylamides, and allyl- and benzylamines (Table 3, entries 6-14). The reaction of diallyl-2-propynylamine is noteworthy as this transformation displayed high selectivity for cyclization of the enyne moiety rather than the diene moiety (Table 3, entry 9). Rhodium-catalyzed enyne cyclization/hydrosilylation tolerated substitution at the alkyne carbon (Table 3, entry 5) and, in some cases, at both the allylic and terminal alkenyl carbon atoms (Equation (7)). 

Several recent publications are focused on allylic and benzylic tosylamida-tions of a range of unsaturated hydrocarbons with Phi = NTs [192-196]. Salen-Mn(III) complexes, Ru(II) and Mn(III)-porphyrins, and Ru(II)- and Ru(III)-amine complexes were employed as catalysts for this purpose, and issues pertaining to catalyst efficiency and enantioselectivity of tosylamidation were addressed. Examples are shown in Scheme 71 [192,193]. 

Koizumi and co-workers used the optically active allylic chloroselenuranes bearing the 2-exo-hydroxyl-10-bornyl group to obtain optically active allylic amines [41]. The treatment of allylic selenides with f-BuOCl gave the corresponding allylic chloroselenuranes as the only product. Benzyl carbamate, t-butyl carbamate, p-tosylamide, and diphenylphosphinamide were selected as the AT-protected amines for selenimide formation. The nucleophilic reaction of... 

The allylic alcohol was subjected to an Eschenmoser-Claisen rearrangement with dimethylacetamide dimethylacetal to introduce the C14 substituent in a stereoselective manner. Reduction of the amide to the corresponding aldehyde with phenyl silane in the presence of Ti(0/Pr)4 was followed by an acid-promoted closure of the C-ring of codeine. In order to prevent N-oxidation, the amine was converted to the corresponding tosylamide, via debenzylation and treatment with tosyl chloride, before the allylic alcohol was introduced by the reaction of the alkene with selenium dioxide (65). The stereochemistry of the C6 hydroxy functionality was corrected by applying the well-known oxidation/reduction protocol [46, 60] before the benzylic double bond was reductively removed under Birch conditions. Codeine (2) was obtained in 17 steps with an overall yield of approximately 0.6%. 

Styrene/allyl benzoate copolymer Styrene/MA copolymer Styrene/PVP copolymer Sucrose acetate isobutyrate Sucrose benzoate Sucrose benzoate/sucrose acetate isobutyrate/butyl benzyl phthalate copolymer Sucrose benzoate/sucrose acetate isobutyrate/butyl benzyl phthalate/methyl methacrylate copolymer Sucrose benzoate/sucrose acetate isobutyrate copolymer TEA-acrylates/acrylonitrogens copolymer Tosylamide/epoxy resin Tosylamide/formaldehyde resin Triacetin Tributyl citrate Tricetyl phosphate Tricontanyl PVP... 

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