在这里,我们描述了1α,25-二羟基维生素D 3(骨化三醇)的通用有效的全合成方法。合成策略依赖于前所未有的Si辅助的氨基甲酸酯通过氨基甲酸酯置换S N 2'-氨基甲酸酯,以将具有挑战性的关键性季铵甲基基团设置在CD-反式-茚满核的稠环连接处。其他关键转化包括用CuH催化α,β,γ,δ-不饱和酯的催化不对称还原,以在C20处生成天然甾体构型,以及进行Pauson-Khand环化反应以形成CD环骨架。这种策略使得能够合成用于结构功能研究和药物开发的新型类似物。
acceleration effect of an allylic hydroxy group on ring-closing enyne metathesis has been found. Ring-closing enyne metathesis of terminalalkynes possessing an allylic hydroxy group proceeded smoothly without the ethylene atmosphere generally necessary to promote the reaction. The synthesis of (+)-isofagomine with the aid of this efficient reaction has been demonstrated. Mechanistic studies of the acceleration
Acceleration effect of allylic hydroxy group on ring-closing enyne metathesis of terminal alkynes: scope and application to the synthesis of isofagomine
substituent effect on ring-closing enyne metathesis has been found. An allylic hydroxy group on enyne substrates accelerates ring-closing enyne metathesis of terminalalkynes. The reaction proceeds smoothly without ethylene atmosphere and/or more reactive newer generation Ru-carbene catalysts, which are generally necessary to promote the reaction. This efficient reaction was applied to the synthesis of
A Ring-Closing Enyne Metathesis Approach to Functionalized Semicyclic Dienes: The Total Synthesis of (-)-Tetrangomycin
作者:Lindon W. K. Moodie、David S. Larsen
DOI:10.1002/ejoc.201301627
日期:2014.3
The angucycline antibiotic (–)-tetrangomycin was synthesized in 13 steps (11 % overall yield) by using a stereoselective Diels–Alder reaction between a naphthoquinone and a semicyclicdiene to construct the benz[a]anthraquinone ring system. The diene intermediates were synthesized through a ring-closingenynemetathesis reaction. The tertiary alcohol at C-3 was installed by an asymmetric dihydroxylation
Regio‐ and Diastereoselective Rhodium‐Catalyzed Allylic Substitution with Unstabilized Benzyl Nucleophiles
作者:Debasis Pal、Timothy B. Wright、Ryan O'Connor、P. Andrew Evans
DOI:10.1002/anie.202008071
日期:2021.2.8
rhodium‐catalyzed allylic substitution of challenging alkyl‐substituted secondary allylic carbonates with benzylzinc reagents, which are prepared from widely available benzyl halides. This process utilizes rhodium(III) chloride as a commercially available, high‐oxidation state and bench‐stable pre‐catalyst to provide a rare example of a regio‐ and diastereoselective allylic substitution in the absence of an
A short, efficient route to 1-hydroxylated vitamin D ring A fragments
作者:José L. Mascareñas、Ana Ma García、Luis Castedo、Antonio Mouriño
DOI:10.1016/s0040-4039(00)74261-4
日期:1992.7
The bis-exocyclic conjugated diene system of vitamin Dring A synthons is efficiently constructed by means of a palladium-catalyzed intramolecular cyclization of the (Z)-iodoalkene resulting from the stereoselective hydrometallation-iodinolysis of propargylic alcohol 9.