Synthesis of d-erythro-Dihydrosphingosine and d-xylo-Phytosphingosine from a Serine-Derived 1,5-Dioxaspiro[3.2]hexane Template
摘要:
[GRAPHICS]A serine-derived 1,5-dioxaspiro[3,2]hexane template is shown to be a useful precursor for both aminodiol and aminotriol sphingoid bases by its conversion to D-erythro-dihydrosphingosine and D-xylo-phytoshingosine.
Synthesis of d-erythro-Dihydrosphingosine and d-xylo-Phytosphingosine from a Serine-Derived 1,5-Dioxaspiro[3.2]hexane Template
摘要:
[GRAPHICS]A serine-derived 1,5-dioxaspiro[3,2]hexane template is shown to be a useful precursor for both aminodiol and aminotriol sphingoid bases by its conversion to D-erythro-dihydrosphingosine and D-xylo-phytoshingosine.
作者:Lisa M. Dollinger、Albert J. Ndakala、Mehrnoosh Hashemzadeh、Gan Wang、Ying Wang、Isamir Martinez、Joel T. Arcari、David J. Galluzzo、Amy R. Howell、Arnold L. Rheingold、Joshua S. Figuero
DOI:10.1021/jo9906072
日期:1999.9.1
The methylenation of beta-lactones 5 with dimethyltitanocene provides a versatile, reliable, and highly chemoselective entry to 2-methyleneoxetanes 7. The conversion proceeds selectively in the presence of alkenes, unprotected alcohols, and a variety of other carbonyl moieties, A study of conditions for the optimization of this reaction is delineated. In addition, the first X-ray structure of a 2-methyleneoxetane, which shows its similarity to related p-lactones, is reported. Reactivity studies of 2-methyleneoxetanes are presented in which it is demonstrated that these compounds are attacked at C-4 with a nucleophile; then, subsequently, the resultant enolate reacted with an electrophile. An interesting dichotomy of reactivity was observed when methyleneoxetane 7c was treated with electrophiles. Reaction of 7c with acetic acid gave acetoxyoxetane 19. When 7c was exposed to bromine, dibromoketone 20 resulted.
The First General Synthesis of 1,5-Dioxaspiro[3.2]hexanes
作者:Albert J. Ndakala、Amy R. Howell
DOI:10.1021/jo981309s
日期:1998.9.1
Synthesis of <scp>d</scp>-<i>e</i><i>rythro</i>-Dihydrosphingosine and <scp>d</scp>-<i>x</i><i>ylo</i>-Phytosphingosine from a Serine-Derived 1,5-Dioxaspiro[3.2]hexane Template
作者:Albert J. Ndakala、Mehrnoosh Hashemzadeh、Regina C. So、Amy R. Howell
DOI:10.1021/ol0200448
日期:2002.5.1
[GRAPHICS]A serine-derived 1,5-dioxaspiro[3,2]hexane template is shown to be a useful precursor for both aminodiol and aminotriol sphingoid bases by its conversion to D-erythro-dihydrosphingosine and D-xylo-phytoshingosine.
Synthesis of <i>epi</i>-Oxetin via a Serine-Derived 2-Methyleneoxetane
作者:Marisa L. Blauvelt、Amy R. Howell
DOI:10.1021/jo7018762
日期:2008.1.1
[GRAPHICS]The unique reactivity of 2-methyleneoxetanes and 1,5-dioxaspiro[3.2]hexanes has been exploited for the synthesis of epi-oxetin (26), an oxetane-containing beta-amino acid. While the preparation of the natural product oxetin (1) was the original goal, the unexpected diastereoselectivity of an precedented reduction provided the epi-oxetin framework. The methodology described herein should be amenable for the preparation of oxetin with a change in nitrogen protection.