Efficient syntheses are described for the new bridging bis-phosphanes DPPN (4) and DPEN (5) built around the restricted rigidity of a 2,7-dialkoxynaphthalene backbone. These show marked preference for bridging pairs of metal atoms (PtII, Mo0) to form metallamacrocycles or oligomers. Single-crystal X-ray structure determinations of four dimeric complexes with PtII and Mo0 are reported. The dimeric platinum
Unusual Carbonyl Differentiation in the Lewis Acid-Catalyzed Allylation of Aldehydes with Tetraallyltin. Applications to Parallel Recognition and Shotgun Process
作者:Yoshifumi Nagano、Akihiro Orita、Junzo Otera
DOI:10.1246/bcsj.76.2183
日期:2003.11
In contrast to conventional substrate selectivity in Lewis-acid promoted nucleophilic reactions wherein less electrophilic aldehydes react preferentially over the more electrophilic counterparts, addition of tetraallyltin to aldehydes occurs in a reversed sense. The substrate selectivity in Lewis acid-promoted nucleophilic addition is generally dependent on the combinations of substrates, nucleophiles