The urea connection. Intramolecular Diels-Alder reactions of ureas

Intramoleeular Diels-Alder reactions with a urea tether afford adducts in good yields, yet the analogous carbamates fail to cycliz

Synthesis of a pentacyclic precursor to the Strychnos alkaloids

An advanced intermediate for the synthesis of the Strychnos alkaloids was constructed by a sequence involving an intramolecular Diels-Alder reaction, alkylation of an enol silyl ether, and conversion of the alkylation product into a pentacyclic lactam

Regiocontrol by Remote Substituents. A Direct Total Synthesis of Racemic Hongconin

The total synthesis of hongconin (1) has been completed. Key steps include the metalation of a benzylic alcohol, the formation of a six-membered ring ether via a mercury-mediated cyclization, and the regioselective installation of the naphthalene ring by way of a Diels-Alder reaction

Synthesis of chelating bidentate isocyano and cyano ligands and their metal complexes

Molecular models indicate that they should chelate to metals with the donor groups at 90° with respect to each other. From reactions of the diisocyano ligand DiNC, the following complexes with chelating DiNC ligands have been isolated: Cr(CO),(DiNC), Mo(CO),(DiNC), W(CO),(DiNC), MII(CO)~(D~NC)B~, CpFe(CO)(DiNC)+, and CpFe(CS)(DiNC)+. The characterization of these complexes demonstrates that DiNC can function as a chelating ligand despite its formation of a 13-member chelate ring

Stereoselective synthesis of calonectrin

Several macrocyclic lactones of the trichothecene class of compounds exhibit significant anticancer activity.\u27 A common structural subunit in each of these lactones is the sesquiterpene verrucarol(1). Anguidin (2), a more highly oxygenated analogue, also shows inhibitory activity against several cancers., Calonectrin (3), considered to be the biogenetic precursor to verru~arol,~ has recently been isolated

The Concept of God in Chrisitian Science

The purpose or this paper is, first, to examine Mrs. Eddy\u27s concept in the light of Scripture and to prove that her concept of God is not Scriptural. In this connection it will be necessary to show how Mrs. Eddy uses Scripture passages in a metaphysical and even perverted manner to substantiate her claims. Secondly, we shall compare her concept of God with those or other religious and philosophic systems and demonstrate the falsity of her claim that her concept of of God is unique

Cycloaddition reactions of bridgehead enones

The cycloaddition reactions of bridgehead enones derived in situ from ketones 8,9, and 10 with various dienes at 0 C afford good yields of adducta. Even 1,1,3-trisubstituted dienes work well. The exclusive exo stereochemistry can be rationalized in terms of a stepwise mechanism involving ionic intermediates

Synthesis of 4,11-dideoxydaunomycinone by a Claisen/Diels-Alder sequence

The synthesis of 3 from ketone 6 by a Claisen/Diels-Alder sequence uncovered some fascinating differences between the benzene and naphthalene series. The most direct pathway to 3 is 6-20-21-16-17-18