an aromaticaldehyde for use in asymmetric synthesis. The reaction between aromaticaldehydes and aryl or allyl electrophiles with a silylboronate utilizing a chiral copper-N-heterocyclic carbene catalyst and a palladium-bisphosphine catalyst in a synergistic manner occurred with high enantioselectivities to deliver the three-component coupling products, chiral silyl-protected secondary alcohol derivatives
Preparation of <i>N</i>-Alkyl 2-Pyridones via a Lithium Iodide Promoted <i>O</i>- to <i>N</i>-Alkyl Migration: Scope and Mechanism
作者:Sarah Z. Tasker、Michael A. Bosscher、Christina A. Shandro、Erica L. Lanni、Keun Ah Ryu、Gregory S. Snapper、Jarrad M. Utter、Bruce A. Ellsworth、Carolyn E. Anderson
DOI:10.1021/jo3015424
日期:2012.9.21
An efficient and inexpensive LiI-promoted O- to N-alkyl migration of 2-benzyloxy-, 2-allyloxy-, and 2-propargyloxypyridines and heterocycles is reported. The reaction produces the corresponding N-alkyl 2-pyridones and analogues under green, solvent-free conditions in good to excellent yields (30 examples, 20–97% yield). This method has been shown to be intermolecular and requires heat and lithium cation
A new chiral catalyst for the enantioselective synthesis of secondary alcohols and deuterated primary alcohols by carbonyl reduction
作者:E.J. Corey、John O. Link
DOI:10.1016/s0040-4039(01)93871-7
日期:1989.1
efficient synthesis of(S)-(−)-2-(di-β-naphthylhydroxymethyl)pyrrolidine (1) makes available the oxazaborolidine derivatives2 and3 which are excellent catalysts for borane reduction of a variety of achiral ketones to chiral secondary alcohols, e.g. acetophenone, 98% ee; α-tetralone, 95% ee; and methyl-4-oxo-4-phenyl butyrate, 96% ee. The synthesis of chiral 1-deuterio primary alcohols fromachiral aldehydes
Stereoselective oxidative coupling and asymmetric hydride reduction related to (–)-(S)-10,10′-dihydroxy-9,9′-biphenanthryl
作者:Koji Yamamoto、Hitoshi Fukushima、Masao Nakazaki
DOI:10.1039/c39840001490
日期:——
Oxidativecoupling of 9-phenanthrol (1) with a (–)-(R)-1,2-diphenylethylamine-copper(II) complex yielded (–)-(S)-10,10′-dihydroxy-9,9′-biphenanthryl (2)(98% optical purity)′ the chiral aluminium hydride reagent modified by (2) was found to exhibit enantioface selectivity towards a variety of prochiral compounds.
Rearrangement of lithiated S-alkyl O,O-dialkyl thiophosphates: Scope and stereochemistry of the thiophosphate–mercaptophosphonate rearrangement
作者:Violeta Philippitsch、Friedrich Hammerschmidt
DOI:10.1039/c1ob05246b
日期:——
S-Alkyl O,O-dialkyl thiophosphates are prepared by alkylation of the triethylammonium salt of O,O-diisopropyl thiophosphoric acid. S-Benzyl thiophosphate was metallated at temperatures of ≥−45 °C by trityllithium and LiTMP (lithium 2,2,6,6-tetramethylpiperidide) and S-alkyl thiophosphates only by LiTMP to give dipole-stabilised carbanions which rearrange to α-mercaptophosphonates in yields of up to
S-烷基O,O-二烷基硫代磷酸酯是通过将O,O-二异丙基硫代磷酸的三乙铵盐烷基化而制得的。S-苄基硫代磷酸酯在≥−45°C的温度下被金属化三苯甲基锂仅通过LiTMP和LiTMP(2,2,6,6-四甲基锂化锂)和S-烷基硫代磷酸酯才能得到偶极稳定的碳负离子,这些碳负离子可以重排为α-巯基膦酸酯,产率最高可达45%。发生金属化时具有很高的初级动力学同位素效应(k H / k D高达≈50)。当使用(R)-N-异丙基-1-苯基乙基氨基锂诱导S-戊基硫代磷酸酯的异构化时,分离出ee值为22%的α-巯基膦酸酯。(R)-S- [1-D 1 ]己基O,O-二异丙基硫代磷酸酯被重排为右旋α-巯基-[1-D 1 ]己基膦酸酯,其(R)-构型由化学相关性确定。硫代磷酸酯-巯基膦酸酯的重排在保留构型的情况下进行。