Synthesis and photoinitiated radical cyclization of allyl- and propynyloxymethyl substituted cyclopentanones to tetrahydrocyclopenta[c]furanols
作者:Nikolay T. Tzvetkov、Jochen Mattay
DOI:10.1016/j.tetlet.2005.09.040
日期:2005.11
Bicyclic cyclopentafuranols were formed by photoinitiated radical cyclization of allyl- and propinyloxymethyl substituted cyclopentanones with high regioselectivity. The irradiations were carried out at a wavelength of 300 nm in aprotic solvents such as benzene and acetonitrile. We could also show that reductive photoinduced electron transfer (PET) of the propynyloxymethyl substituted cyclopentanone 5 does not lead to any cyclization. The starting materials were synthesized in good yields following known procedures. (c) 2005 Elsevier Ltd. All rights reserved.
Baeyer-Villiger oxidations catalyzed by engineered microorganisms: Enantioselective synthesis of δ-valerolactones with functionalized chains
作者:Shaozhao Wang、Gang Chen、Margaret M Kayser、Hiroaki Iwaki、Peter C.K Lau、Yoshie Hasegawa
DOI:10.1139/v02-035
日期:2002.6.1
Cyclohexanonemonooxygenase (CHMO) from Acinetobacter sp NCIMB 9871 expressed in baker's yeast and in E. coli and cyclopentanone monooxygenase (CPMO) from Comamonas (previously Pseudomonas) sp. NCIMB 9872 expressed in E. coli are new bioreagents for Baeyer-Villigeroxidations. These engineered microorganisms, requiring neither biochemical expertise nor equipment beyond that found in chemical laboratories
Sequential Ketyl−Olefin Coupling/β-Elimination Reactions Mediated by Samarium(II) Iodide
作者:Gary A. Molander、Christina R. Harris
DOI:10.1021/jo971889d
日期:1998.2.1
Samarium(II) iodide (SmI(2)) has been employed in an intramolecular sequential ketyl-olefin coupling/beta-elimination reaction. The overall process results in the net addition of an alkenyl species to a ketone carbonyl. This novel protocol for the intramolecular delivery of an alkenyl moiety avoids the basic reaction conditions typical of nucleophilic additions that are mediated by alkenylmagnesium