Catalytic Asymmetric Enyne Addition to Aldehydes and Rh(I)-Catalyzed Stereoselective Domino Pauson–Khand/[4 + 2] Cycloaddition
作者:Wei Chen、Jia-Hui Tay、Jun Ying、Xiao-Qi Yu、Lin Pu
DOI:10.1021/jo3026065
日期:2013.3.15
propargylic alcohols prepared from the catalyticasymmetric enyne addition to aliphatic aldehydes are used to prepare a series of opticallyactive trienynes. In the presence of a catalytic amount of [RhCl(CO)2]2 and 1 atm of CO, the opticallyactive trienynes undergo highly stereoselective domino Pauson–Khand/[4 + 2] cycloaddition to generate opticallyactive multicyclic products. The Rh(I) catalyst
optical activity of the starting aniline was observed in the acid-catalyzedrearrangement of (−)-(S)-2,6-dimethyl-N-[1′-(p-tolyl)prop-2′-ynyl]aniline ((−)-42; cf. Scheme 25). N-[1′-(p-anisyl)prop-2-ynyl]-2,4,6-trimethylaniline(43; cf. Scheme 25) underwent no acid-catalyzed [3,3]-sigmatropic rearrangement at all. The acid-catalyzedrearrangement of N-(1′,1′-dimethylprop-2′-ynyl)aniline (25; cf. Scheme 10)
N-(1',1'-二甲基丙-2'-炔基)-,N-(1'-甲基丙-2'-炔基)-和N-(1'-芳基丙-2'的酸催化重排-Nyn)-2,6-,2,4,6-,2,3,5,6-和2,3,4,5,6-取代的苯胺在1N H 2 SO 4水溶液和ROH的混合物中例如EtOH,PrOH,BuOH等,或在CDCl 3或CCl 4中,在4至9摩尔当量的存在下。三氟乙酸(TFA)进行了研究(参见方案12 - 25和表6和7)。CDCl中N-(3'-X-1',1'-二甲基-丙-2'-炔基)-2,6-和2,4,6-三甲基苯胺(X = Cl,Br,I)的重排3/ TFA在20℃已经发生与τ 1/2 CA的 1至5小时得到相应的6-(1-X-3'-甲基丁基-1,2'-二烯基)-2,6-二甲基-或2,4,6-三甲基环己-2,4-二烯-1 -亚胺离子(参见方案13和脚注26和34)当4位未被取代时,会发生连续的[3,3]-σ重排,从而生成2
Highly Enantioselective Addition of Trimethylsilylacetylene to Aldehydes Catalyzed by a Zinc-Amino-Alcohol Complex
A fine addition! A highlyenantioselective and efficient procedure for the amino‐alcohol–zinc‐catalyzedaddition of trimethylsilylacetylene to aromatic, α,β‐unsaturated, and aliphatic aldehydes has been developed (see scheme; R=aryl, alkynyl, or alkyl; TMS=trimethylsilyl; TBDMS=tert‐butyldimethylsilyl). The present protocol was successfully applied in the concise synthesis of the natural products marine
很好的补充!已开发出一种高度对映选择性和高效的程序,用于氨基醇锌催化的三甲基甲硅烷基乙炔加成到芳族,α,β-不饱和和脂肪族醛中(见方案; R =芳基,炔基或烷基; TMS =三甲基甲硅烷基; TBDMS =叔丁基二甲基甲硅烷基)。本协议已成功地应用于天然产物海洋炔醇和法卡林二醇的简明合成中。
SYNTHESIS, STRUCTURE AND USE OF BISOXAZOLIDINES FOR ASYMMETRIC CATALYSIS AND SYNTHESIS
申请人:Wolf Christian
公开号:US20070265255A1
公开(公告)日:2007-11-15
One aspect of the invention relates to chiral bisoxazolidines and their use in asymmetric catalysis. The chiral bisoxazolidines are a novel class of compounds that is expected to find multiple applications, for example, in asymmetric synthesis. For example, a bisoxazolidine ligand enabled the catalytic enantioselective alkynylation and alkylation of a range of aromatic and aliphatic aldehydes, generating chiral propargylic alcohols and secondary alcohols in high yields and enantiomeric excess.
Gold-Catalyzed Regioselective Hydration of Propargyl Acetates Assisted by a Neighboring Carbonyl Group: Access to α-Acyloxy Methyl Ketones and Synthesis of (±)-Actinopolymorphol B
作者:Nayan Ghosh、Sanatan Nayak、Akhila K. Sahoo
DOI:10.1021/jo101995g
日期:2011.1.21
suitable to perform hydration of TMS-substituted propargyl acetates, even though it requires prolonged reaction time for completion. Stereointegrity of the propargylic acetate is preserved during the hydration. The robustness of the system is successfully demonstrated through gram scale preparation of the product in nearly quantitative yield. The common α-acyloxy methylketone is transformed to 1,2-diol