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• 33467-76-4 (E)-hept-2-en-1-ol 
• 98-59-9 p-toluenesulfonyl chloride 

Relevant academic research and scientific papers

Stereoselective synthesis of (-)-lepadins A-C

A concise synthesis of the marine alkaloids (-)-lepadins A-C from a phenylglycinol-derived tricyclic lactam is reported. Key steps from the stereochemical standpoint involve stereoselective cyclocondensation, double bond hydrogenation, oxazolidine opening

Supramolecular catalysis of unimolecular rearrangements: Substrate scope and mechanistic insights

A cavity-containing metal-ligand assembly is employed as a catalytic host for the 3-aza Cope rearrangement of allyl enammonium cations. Upon binding, the rates of rearrangement are accelerated for all substrates studied, up to 850-fold. Activation parameters were measured for three enammonium cations in order to understand the origins of acceleration. Those parameters reveal that the supramolecular structure is able to reduce both the entropic and enthalpic barriers for rearrangement and is highly sensitive to small structural changes of the substrate. The space-restrictive cavity preferentially binds closely packed, preorganized substrate conformations, which resemble the conformations of the transition states. This hypothesis is also supported by quantitative NOE studies of two encapsulated substrates, which place the two reacting carbon atoms in close proximity. The capsule can act as a true catalyst, since release and hydrolysis facilitate catalytic turnover. The question of product hydrolysis was addressed through detailed kinetic studies. We conclude that the iminium product must dissociate from the cavity interior and the assembly exterior before hydroxide-mediated hydrolysis, and propose the intermediacy of a tight ion pair of the polyanionic host with the exiting product.

Enantioselective diene cyclization/hydrosilylation catalyzed by optically active palladium bisoxazoline and pyridineoxazoline complexes

A 1:1 mixture of (N-N)Pd(Me)Cl [N-N = (S,S)-4,4'-dibenzyl-4,5,4',5'- tetrahydro-2,2'-bisoxazoline] (S,S-4a) and NaBAr4 [Ar = 3,5-C6H3(CF3)2] (5 mol %) catalyzed the asymmetric cyclization/hydrosilylation of dimethyl diallylmalonate (2) and triethylsilane at -30 °C for 48 h to form an 8.1:1 mixture of the silylated carbocycle (S,S)-trans-1,1-dicarbomethoxy-4-methyl- 3-[(triethylsilyl)methyl]cyclopentane (S,S-3) (95% de, 72% ee) and dimethyl 3,4-dimethylcyclopentane-1,1-dicarboxylate (S,S-6) in 64% combined yield. In comparison, a 1:1 mixture of the palladium pyridineoxazoline complex (N- N)Pd(Me)Cl [N-N = (R)-(+)-4-isopropyl-2-(2-pyridinyl)-2-oxazoline] (R-5b) and NaBAr4 (5 mol %) catalyzed the asymmetric cyclization/hydrosilylation of 2 and triethylsilane at -32 °C for 24 h to form carbocycle S,S-3 in 82% yield (>95% de, 87% ee) as the exclusive product. Asymmetric diene cyclization catalyzed by complex R-5b was compatible with a range of functional groups and produced carbocycles with up to 91% ee. The procedure also tolerated substitution at a terminal olefinic position and at the allylic position of the diene.