Alkenylzinc-Mediated Approach to the Vitamin D Skeleton. Application to the Synthesis of 6-Methyl Analogs of Vitamin and Previtamin D
摘要:
Palladium-catalyzed cross-coupling of alkenylzine reagents, bearing the C,D-ring/side chain portion, and (Z)-1-iodo-1,3-bis-exocyclic dienes (as A-ring precursors), provides a mild, convergent entry to the vitamin D skeleton, that is suitable for the synthesis of thermally labile derivatives such as those bearing substituents on the triene system.
Alkenylzinc-Mediated Approach to the Vitamin D Skeleton. Application to the Synthesis of 6-Methyl Analogs of Vitamin and Previtamin D
摘要:
Palladium-catalyzed cross-coupling of alkenylzine reagents, bearing the C,D-ring/side chain portion, and (Z)-1-iodo-1,3-bis-exocyclic dienes (as A-ring precursors), provides a mild, convergent entry to the vitamin D skeleton, that is suitable for the synthesis of thermally labile derivatives such as those bearing substituents on the triene system.
Substrate control of diastereoselectivity in zirconium (II) mediated enyne cyclizations
作者:Brian L. Pagenkopf、Eric C. Lund、Tom Livinghouse
DOI:10.1016/0040-4020(94)01130-r
日期:1995.4
The reductive cyclization of an extensive series of chiral enynes by Cp2Zr(II) complexes has been examined. In most instances excellent substrate control of cyclization stereochemistry was observed.
作者:José L. Mascareñas、Ana Ma Garcia、Luis Castedo、Antonio Mouriño
DOI:10.1016/s0040-4039(00)60832-8
日期:——
The application of Negishi's cyclization methodology to the synthesis of (Z)-1-iodo-1,3-bis-exocyclic-dienes from acyclic precursors is described. This kind of compounds can be used for the preparation of conjugated systems such us the triene of vitamin D.
On the origin of diastereoselection in the cyclization of enynes on low-valent zirconium centers. Substituent and torsional effects on annulation stereochemistry