[reaction: see text] An efficient synthesis of highly substituted alpha-arylnaphthalene analogues has been developed utilizing Lewis acid-promoted regiocontrolled benzannulation of aryl(aryl')-2,2-dichlorocyclopropylmethanols (aryl not equal aryl'; abbreviated as AACMs). Both AACM diastereomers were easily prepared via highly stereoselective addition (>95/5) of ArLi to gem-dichlorocyclopropropyl aryl' ketones. The choice of Lewis acids determined the cyclization regioselectivity of the present benzannulation. TiCl4 and SnCl4 used the chelation pathway, whereas silyl triflates used a nonchelation pathway to give unsymmetrically substituted regioisomeric alpha-arylnaphthalenes in 40-91% yields with moderate to excellent regioselectivity (TiCl4 or SnCl4; >99/1-3/1, TBDMSOTf; >1/99-1/4). Thus, the alpha-aryl or alpha-aryl' moiety (accessory aryl group) was alternatively introduced to alpha-arylnaphthalenes by choosing either the order of the reaction sequences or the appropriate catalyst. Application of the present method to the total synthesis for unsymmetrically substituted natural lignan lactones, justicidin B, retrojusticidin B, dehydrodesoxypodophyllotoxin, and a related analogue, 5'-methoxyretrochinensin, was demonstrated. Lignan retrolactones (retrojusticidin B and 5'-methoxyretrochinensin) were synthesized by the conventional lactonization of the diol precursor, whereas a novel Bu2SnO-mediated monoacylation method was applied to the synthesis of normal lignan lactones (justicidin B and dehydrodesoxypodophyllotoxin).

The RCCJ gene has been isolated from several vertebrates, including human, hamster and Xenopus.Genes similar to RCCI, namely BJJ and SRMI/PRP20, have been isolated from the insect Drosophila and from the budding yeast Saccharomyces cerevisiae. A mutation of the RCCI gene in the hamster BHK21 cell line, tsBN2, confers pleiotropic phenotypes, including Gl arrest and premature induction of mitosis in cells synchronized at the Gl/S boundary. Similarly, mutations of the SRMI/PRP20 gene are pleiotropic: the srml mutant shows Gi arrest and suppression of the mating defect of mutants lacking pheromone receptors, and the prp2O mutant shows an alteration in mRNA metabolism. Here we show that both BJI and SRMI/PRP20 complement the temperature sensitive phenotype of the tsBN2 cells. Like RCC1 proteins of vertebrates, the protein products of the Drosophila and yeast RCCI homologues were located in the nuclei of the mammalian cells. These results suggest that the BJJ and SRMI/PRP20 genes are functionally equivalent to the vertebrate RCCI genes, and that the RCCI gene plays an important role in the regulation of gene expression in the eukaryotic cell cycle.

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