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A small library of novel 2-oxo-1,2,3,4-tetrahydropyrimidines was synthesized via a one-pot multicomponent Biginelli reaction. Copper complex [Formula: see text] which was used for the first time as a homogeneous and heterogeneous catalyst, makes this a facile and efficient reaction at room temperature. All the obtained products fall out of the solution in pure form and are easily isolated via filtration in good-to-excellent yields. The molecular structure of one of the products, ethyl 6-methyl-2-oxo-4-(4[Formula: see text]-isopropoxy-3[Formula: see text]-methoxyphenyl) - 1,2,3,4 - tetrahydropyrimidine-5- carboxylate, has been determined by X-ray crystallography. All non-hydrogen atoms in the heterocyclic, six-membered ring are determined to be approximately coplanar.

A convenient two-step protocol prepa-ration of cineol (1-isopropyl-4-methyl-7-oxabicyclo-[2,2,1]heptane) from -terpineol (p-menth-1-en-8-ol)is reported. The phenylselenoetherification of -ter-pineol with PhSeX (X = Cl, Br, I) as a key step isdescribed. -Terpineol reacts with PhSeX to form thecorresponding phenylselenoether in short reactiontime and in quantitative yield. A subsequent reduc-tion with Bu 3 SnH to cineol proceeds in high yield(98%) C 2004 Wiley Periodicals, Inc. Heteroatom Chem15:468–470, 2004; Published online in Wiley InterScience(www.interscience.wiley.com). DOI 10.1002/hc.20044 INTRODUCTION Cyclofunctionalization of unsaturated alcohols is avery popular reaction providing easy access to cyclicether products [1–6]. In many respects, selenocy-clofunctionalization has the advantage that the in-troduction of the heteroatom, the manipulation ofthe obtained product, and the removal of the func-tion are facilitated by simple and mild condition re-quired [5–7]. This methodology has been extendedto more complex system having alcohol and doublebond functions.Cyclization of unsaturated alcohols leading tocyclic ethers is well documented in the literature

Primary and secondary alcohols, e.g. (I), react to give tetrahydropyrans whereas tertiary alcohols such as (IV) yield tetrahydrofurans.

A fast and efficient method for intramolecular heterocyclization of (Z)- and (E)-hex-4-en-1-ols was developed. The method does not cause side reactions of the substrates and provides the cyclic phenylselenoethers in high yields after only few minutes. A catalytic amount of SnCl2 increased the yield, but in the presence of an equimolar amount of SnCl2, formation of corresponding cyclic ethers were almost quantitative and reaction occurred instantaneously under extremely mild experimental conditions.

An efficient protocol for the preparation of phenylselenoethers from unsaturated alcohols using phenylselenenyl halides at room temperature was developed. The procedure employs phenylselenenyl chloride and bromide, some Δ 4- and Δ 5-alkenols and Ag2O, as an additive, to generate the tetrahydropyrans or tetrahydrofurans. This method permits the preparation of cyclic phenylselenoethers in high yields and under extremely mild conditions.

An improved procedure for intramolecular cyclization of some Δ5-alkenols, using PhSeX (X = Cl, Br) has been developed. We found that cyclization can be facilitated in the presence of pyridine, Ag2O, and some Lewis acids as catalysts. Thus catalytic amount of additives (pyridine and Ag2O) influences higher yields but equimolar amount achieves almost quantitative yield under extremely mild experimental conditions. In the presence of Lewis acids (ZnCl2 and FeCl3) high yields of cyclic ether products are obtained with catalytic amounts. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:146–149, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10227

An improved procedure for intramolecular cyclization of some Δ5-alkenols using PhSeX (X=Cl, Br) was developed. We found that cyclization can be facilitated in the presence of pyridine, Ag2O, and AgOAc as additives. Thus, a catalytic amount of additive influenced higher yields and equimolar amounts achieved almost quantitative yields under extremely mild experimental conditions. The effect of the halide ion of the selenylating reagent was not significant.

The reaction of some alkenols with tetrachloromethane in the presence of a radical initiator was investigated. Regarding the effects of structural features of the starting alkenol (number and position of methyl substituents at the double bond and at the carbinol carbon atom, constitutional relationship between the double bond and the hydroxyl group) there are two possible competing reactions: addition and cyclization. In the case of the simplest alkenols (without substituents and with a more remote double bond) addition occurs; mono- and disubstituted secondary and tertiary Δ4- and Δ5-alkenols cyclize in high yields to give the corresponding cyclic ethers.