Yoshiaki Nagano

PdCl2(MeCN)2-catalyzed carbonylation of diethylamine with carbon dioxide: Selective synthesis of tetraethylurea and diethylformamide

Abstract The reaction of diethylamine with carbon dioxide (CO2) with PdCl2(MeCN)2 as a catalyst gives tetraethylurea(1) or diethylformamide(2) selectively under mild reaction conditions by employing the PPh3/CCl4/MeCN and the HCOONa/methyl cellosolve systems, respectively.

Medium-sized Cyclophanes. Part 44.1Synthesis and Stereochemical Assignments of 9-Substituted2,11-Dithia[3.3]metacyclophanes

Various syn- and anti-9-substituted 2,11-dithia[3.3]metacyclophanes are obtained by the coupling reaction of the corresponding 2,6-bis(bromomethyl)benzenes and 1-substituted 2,6-bis(sulfanylmethyl)-4-tert-butylbenzenes under highly diluted conditions in 10% ethanolic KOH in the presence of a small amount of NaBH 4 .

Medium-sized Cyclophanes. Part 40.1Generation of a Bis(o-quinone methide) from[n.2]Cyclophanes having a Spiro Skeleton and theirTrapping Reaction with Nucleophiles and Dienophiles

Spiro compounds 2, obtained from the oxidation of dihydroxy[n.2]metacyclophanes 1 with K 3 Fe(CN) 6 , readily generate a bis(o-quinone methide) 3 with mild heating which is trapped with nucleophiles and dienophiles to give diarylalkanes 4–6 and [4+2] cycloadducts 8, respectively.

Medium-sized Cyclophanes. Part 42.1Synthesis of [2.n]Metacyclophan-1-ones and[2.n]Metacyclophane-1,2-diones

Acetolysis of 10-endo,11-exo-dibromo-6,14-di-tert-bu tyl-9,17-dimethyl[3.2]metacyclophane cis-3b afforded the corresponding 10,11-diacetoxy derivative cis-5b with retention of configuration, whereas in the case of [4.2]metacyclophane cis-3c the same stereoselectivity was not observed: the diacetoxy derivatives 5 were converted into a 10,11-dione 10b and a 11,12-dione 10c via hydrolysis followed by Swern oxidation of dihydroxy derivatives 7b and 7c.

Selective Preparation of Polycyclic Aromatic Hydrocarbons. Part 7.1 A Preparative Route to 10,11-Dihydro-5H-dibenzo[a,d]cyclohept enes using Friedel–Crafts Intramolecular Cyclobenzylation

A convenient, mild, one-pot synthesis of substituted dibenzo[a,d]cycloheptenes involving the action of ClCH 2 OMe and TiCl 4 on a variety of diphenylethanes,† which incorporates chloromethylation of a hydrocarbon followed by a Friedel–Crafts intramolecular cyclization reaction, is described.