Enantiospecific syntheses of pseudopterosin aglycones. Part 1. Synthesis of the putative aglycone of pseudopterosin G–J via an A→AB→ABC annulation strategy
摘要:
候选的伪紫葳素 G–J 的苷元及其对映体是分别从 2,3-二甲氧基甲苯和钼及铁的 η³-烯丙阳离子复合物中以对映特异性合成的。A→AB→ABC 闭环策略涉及使用烯丙阳离子或其等效物来创建三个苯基立体中心。四氢萘 (−)-41a 的 X 射线结构已被确定。
The regioselectivity and the stereoselectivity of the hydroboration of N-alkylallylphosphoramide was examined. This study shows the preferential formation of γ-boron derivatives (90 to 100%) and the excellent stereospecificity of the reaction (100% (Z) configuration).
Synthesis of 1-Substituted 1,2-Bis(trimethylsilyl)ethenes via Hydroboration of 1,2-Bis(trimethylsilyl)ethyne with Dialkylborane
作者:Masayuki Hoshi、Yuzuru Masuda、Akira Arase
DOI:10.1246/bcsj.66.914
日期:1993.3
2-bis(trimethylsilyl)ethenyl]dialkylborane. In situ treatment of the above alkenylborane with iodine in the presence of aqueous sodium hydroxide provides highly pure (E)-1-alkyl-1,2-bis(trimethylsilyl)ethene whose alkyl group migrates from the boron atom. Successive treatment of [(Z)-1,2-bis(trimethylsilyl)ethenyl]dicyclohexylborane with copper(I) iodide, allyl bromide, and aqueous sodium hydroxide affords
The core structure of the macrolactone cruentaren A (1) was prepared via a ring-closing alkyne metathesis reaction. The corresponding ester 33 was constructed from the benzoic acid derivative 14 and the diol 30. As a key step in the synthesis of acid 14, an aldol reaction resulted in the required anti-OH/Me pattern. The anti-configuration in the stereotetrad of diol 30 was established by a Marshall
Total synthesis of (±)-6-deoxycastanospermine: an application of the addition of organoboronates to N-acyliminium ions
作者:Robert A Batey、D.Bruce MacKay
DOI:10.1016/s0040-4039(00)01790-1
日期:2000.12
An efficient synthesis of (±)-6-deoxycastanospermine is reported, using a diastereoselective coupling of organoboronates with N-acyliminiumions as the key step. The construction of the indolizidine ring system is completed using a subsequent reductive amination reaction.
An Improved Method for Stereoselective Synthesis of (<i>E</i>)-Alkenes via Alkenyldialkylboranes
作者:Masayuki Hoshi、Yuzuru Masuda、Akira Arase
DOI:10.1246/bcsj.59.3985
日期:1986.12
Successive treatments of alkenyldialkylboranes, formed by the reaction of alkynes and sterically hindered dialkylboranes, with alkyllithium and benzenesulfenyl chloride afforded highly pure (E)-alkenes in good or excellent yields.