AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

A convergent asymmetric synthesis of the polyether antibiotic ferensimycin B has been completed. Chiral enolate bond constructions were employed to establish seven of the 16 stereocenters of the subunits 35 and 52, which comprise the C1-C-9 and C-10-C23 portions of ferensimycin B. The stereogenic centers at C3, C4, C-9, C-10, C-16, C-17, and C18 were incorporated through internal asymmetric induction, while those at C20 and C21 were established by using asymmetric epoxidation methodology. In this transformation, a vanadium-catalyzed internal epoxidation of a bis-homoallylic alcohol was employed to relay chirality from the C-13 to the C-16 oxygen-bearing stereocenter. A final aldol addition reaction on intermediates devoid of protecting groups united the fragments 52 and 35 to provide synthetic ferensimycin B, whose absolute configuration was found to be[GRAPHICS]the same as that of the closely related ionophore lysocellin. This synthesis thus establishes the absolute configuration of ferensimycin B.

AbstractUsing the optimized conditions A), B) or C) for oxidative macrocyclization, the cyclic products (III), (V) and (VII) can be prepared in good yields.

Significant enhancement of trans(anti) stereoselectivity is achieved in rhodium(II) acetamide catalyzed cyclopropanation reactions of 2,3,4-trimethyl-3-pentyl diazoacetate (ODA) and diazoacetamides.