Palladium-Catalyzed Asymmetric Synthesis of 2-Alkynyl Oxacycles
作者:David S. B. Daniels、Amber L. Thompson、Edward A. Anderson
DOI:10.1002/anie.201105720
日期:2011.11.25
cyclizations of cyclic and acyclic propargylic carbonates give 2‐alkynyl oxacycles. The reactions proceed with very high stereoselectivity for both syn‐ and anti‐disubstituted furans and pyrans, and with exceptional regioselectivity. In addition, two‐directional cyclizations of bis‐propargylic carbonate substrates yield bifurans with complete stereocontrol for all diastereomers.
Enantioselective Ketone Hydroacylation Using Noyori’s Transfer Hydrogenation Catalyst
作者:Stephen K. Murphy、Vy M. Dong
DOI:10.1021/ja4021974
日期:2013.4.17
An enantioselectiveketone hydroacylation enables the direct preparation of lactones from keto alcohols. The alcohol is oxidized in situ to an aldehyde, obviating the need to prepare sensitive keto aldehyde substrates. Noyori's asymmetric transferhydrogenationcatalyst was applied to address challenges of reactivity, chemoselectivity, and enantioselectivity.
The preparation of α,β-acetylenic ketones by condensation of lithium acetylides with lactones
作者:John C. Chabala、John E. Vincent
DOI:10.1016/s0040-4039(01)85419-8
日期:——
An efficient Synthesis of Acetylenic ?- and ?-Hydroxy Ketones, ?- and ?-keto acids, and ?- diketones via addition of 1-alkinyllithium compounds to ?- and ?-lactones
作者:Christine Wedler、Hans Schick
DOI:10.1002/prac.19933350503
日期:——
2-Hydroxy-6-alkyn-5-ones 3, 1-hydroxy-5-alkyn-4-ones 4, and 1-hydroxy-6-alkyn-5-ones 5 are conveniently obtained in exellent yields through a highly selective monoaddition of an 1-alkynyllithium compound 2 to gamma-valerolactone (1 a), gamma-butyrolactone (1 b) or delta-valerolactone (1 c). They are oxidized by pyridinium dichromate or Jones reagent to the corresponding acetylenic 1,4-diketones 6, 4-oxo carboxylic acids 7, and 5-oxo carboxylic acids 8, respectively.