Iterative asymmetric synthesis of protected anti-1,3-polyols
摘要:
A new general method for the iterative asymmetric synthesis of anti-1,3-polyol chains has been developed. The alpha,alpha'-bisalkylation of 2,2-dimethyl-1,3-dioxan-5-one SAMP-hydrazone 1 with benzyloxymethylchloride as the second electrophile leads to virtually diastereo- and enantiopure substituted 2,2-dimethyl-1,3-dioxan-5-ones with good overall yields. Their deoxygenation and conversion into primary iodides affords the electrophile for the further alkylation of 1. In this way the configurations of all new stereogenic centres are controlled by a single auxiliary. (C) 1999 Elsevier Science Ltd. All rights reserved.
Iterative asymmetric synthesis of protected anti-1,3-polyols
摘要:
A new general method for the iterative asymmetric synthesis of anti-1,3-polyol chains has been developed. The alpha,alpha'-bisalkylation of 2,2-dimethyl-1,3-dioxan-5-one SAMP-hydrazone 1 with benzyloxymethylchloride as the second electrophile leads to virtually diastereo- and enantiopure substituted 2,2-dimethyl-1,3-dioxan-5-ones with good overall yields. Their deoxygenation and conversion into primary iodides affords the electrophile for the further alkylation of 1. In this way the configurations of all new stereogenic centres are controlled by a single auxiliary. (C) 1999 Elsevier Science Ltd. All rights reserved.
Synthesis of (3<i>R</i>,5<i>R</i>)-harzialactone A and its (3<i>R</i>,5<i>S</i>)-isomer
作者:Gowravaram Sabitha、Rangavajjula Srinivas、Sukant K Das、Jhillu S Yadav
DOI:10.3762/bjoc.6.8
日期:——
The total synthesis of (3R,5R)-harzialactone A (1) and its (3R,5S)-isomer (2) is described. Epoxide opening with thioacetal and diastereoselective reductions are used as key reactions.
报道了(3R,5R)-harzialactone A (1)及其(3R,5S)-异构体(2)的全合成。关键反应包括硫代醇和立体选择性还原的环氧开放反应。
Chemoenzymatic asymmetric synthesis of harzia lactone A stereomers
作者:Abha N. Kumar、Suchitra Bhatt、Subrata Chattopadhyay
DOI:10.1016/j.tetasy.2009.01.009
日期:2009.2
A facile chemoenzymatic synthesis of the harzia lactone A enantiomers was developed. A lipase-catalyzed acylation and an enantio-controlled substrate and reagent-con trol led Sharpless' asymmetric dihydroxylation are the key features of the synthesis. (C) 2009 Elsevier Ltd. All rights reserved.