Synthesis of naturally occuring quinones. Part 20. Tandem Michael/Diels-Alder addition as a new strategy toward tetracyclic systems: synthesis of 11-deoxyanthracyclinones
Synthesis of naturally occuring quinones. Part 20. Tandem Michael/Diels-Alder addition as a new strategy toward tetracyclic systems: synthesis of 11-deoxyanthracyclinones
Trichloro-(<i>trans</i>-2,4-pentadienyl)stannane as a Less Electron-rich Diene and Its Application to Tandem Michael/Diels–Alder Reaction. Formal Total Synthesis of 11-Deoxydaunomycinone
Trichloro-(trans-2,4-pentadienyl)stannane effectively reacted with an acryloylnaphthoquinone to afford tandem Michael/Diels–Alder adduct in excellent yield. The obtained tetracyclic quinone was converted to 11-deoxydaunomycinone precursor.
deficiency of The pentadienyl moiety in pentadienyltrichlorotin is evident as is the case with allyltrichlorotins. Highly fluxional structure of (Z)-pentadienyltrichlorotins is revealed. Interaction between someallyltins and BF3· OEt2 is also demonstrated.
各种烯丙基三烷基锡在-50℃下与典型的路易斯酸SnCl 4反应。具有较少取代烯丙基的锡化合物可立即干净地通过S E 2'途径通过金属转移生成相应的烯丙基三氯锡,而具有更多取代基的锡三氯锡则产生沉淀。巴豆基三丁基锡和SnCl 4首先提供(1-甲基烯丙基)三氯锡,然后异构化为巴豆基三氯锡。戊二烯基三氯锡中戊二烯基部分的电子缺乏是明显的,烯丙基三氯锡是这种情况。揭示了(Z)-戊二烯基三氯锡的高通量结构。还表明了一些烯丙基锡与BF 3 ·OEt 2之间的相互作用。
Optically active pentadienyltin reagent and its application to asymmetric synthesis of (R)-7,11-dideoxydaunomycinone
Highly opticallyactive 2-substituted 2,4-pentadienyltin reagent was synthesised and applied to an efficient asymmetricsynthesis of (R)-7,11-dideoxydaunomycinone by means of tandem Michael/Diels–Alder reaction in a key step.