Double Conjugate Addition of Dithiols to Propargylic Carbonyl Systems To Generate Protected 1,3-Dicarbonyl Compounds
作者:Helen F. Sneddon、Alexandra van den Heuvel、Anna K. H. Hirsch、Richard A. Booth、David M. Shaw、Matthew J. Gaunt、Steven V. Ley
DOI:10.1021/jo052514s
日期:2006.3.31
methoxide to a wide variety of propargylic carbonyl containing compounds. The products of these reactions are differentiated, 1,3-dicarbonyl systems useful for various synthesis programs. By judicious use of hydroxylated substrates tandem cyclization occurs to afford tetrahydropyran lactols or, in the case of hydroxy-substituted propargylic esters, lactones. The corresponding amino-substituted propargylic
Synthetic Studies on Azaspiracid, a Novel Shellfish Poison: Attempts to Construct the ABCD Ring System
作者:Shigeru Nishiyama、Yuichi Ishikawa
DOI:10.3987/com-03-9952
日期:——
Synthesis of the ABCD ringsystem of azaspiracid (1) was attempted. Construction of the highly substituted tetrahydrofuran (9) via the Pd(0)-mediated cyclization, followed by spirocyclization afforded trispiro-ring (28), carrying an unnatural ring-junctions. The BCD ringsystem of 1 was successfully produced by using the bridge of a sulfur atom between the B and C ring to control the spiroacetal center