Remarkable effect of valence electrons in thiolato-bridged diruthenium complexes toward catalytic dimerization of α-methylstyrenes
The dicationic diruthenium complex 1c (RuIII-RuIII) catalytically promotes the dimerization of α-methylstyrenes into the corresponding acyclic dimers, while the use of the mixed-valence diruthenium complex (RuIII-RuIV) generated from 1c and cinnamyl chloride as an active catalyst affords the corresponding indanes via cyclization of the acyclic dimers. The selectivity of the catalytic dimerization of α-methylstyrenes depends on the nature of electrophilicity due to valence electrons in the diruthenium cores between RuIII-RuIII and RuIII-RuIV.
Synthesis of isochromene and related derivatives by rhodium-catalyzed oxidative coupling of benzyl and allyl alcohols with alkynes
The straightforward synthesis of isochromene derivatives and related cyclic ethers is achieved by the rhodium-catalyzed oxidative coupling of α,α-disubstituted benzyl and allyl alcohols with alkynes. The hydroxy groups effectively act as the key function for the regioselective C-H bond cleavage.
The ritter reaction under truly catalytic bronsted acid conditions
Simple organic acids like 2,4-dinitrobenzenesulfonic acid (DNBSA) catalyze the Ritter reaction of secondary benzylic alcohols giving rise to the corresponding N-benzylacetamides in usually high yields. Reactions can be conducted without exclusion of oxygen and without the need of dry solvents. With tertiary α,α-dimethylbenzylic alcohols a different pathway involving a formal dimerization reaction takes place under the acid-catalytic conditions used. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
Sanz, Roberto,Martinez, Alberto,Guilarte, Veronica,Alvarez-Gutierrez, Julia M.,Rodriguez, Felix
p. 4642 - 4645
(2008/03/12)
SYNTHETIC PHOTOCHEMISTRY. XXVIII. A PHOTOCHEMICAL C5-HOMOLOGATION OF 4-ISOPROPENYLTOLUENE WITH METHYL 2,4-DIOXOPENTANOATE TO ISOLAURENE AND A FORMAL SYNTHESIS OF CUPARENE.
Starting from the photocycloaddition of methyl 2,4-dioxopentanoate with 4-isopropenyltoluene, isolaurene was synthesized, and its further conversion to 5-cuparenone constituted the formal synthesis of cuparene. For the first time, the proto-(2 plus 2) pi
Takeshita,Mori,Nakamura
p. 3152 - 3155
(2007/10/02)
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