Synthesis of 4,5-Diazaspiro[2.3]hexanes and 1,2-Diazaspiro[3.3]heptanes as Hexahydropyridazine Analogues
作者:Alpa K. Pancholi、Greg P. Iacobini、Guy J. Clarkson、David W. Porter、Michael Shipman
DOI:10.1021/acs.joc.7b02622
日期:2018.1.5
5-Diazaspiro[2.3]hexanes are made by dihalocarbene addition across the exocyclic double bond of readily accessible 3-alkylidene-1,2-diazetidines. Using difluorocarbene, generated from TMSCF3/NaI, these spirocycles were produced in yields up to 97% by stereospecific addition across the alkene. Lower yields (up to 64%) were observed using more reactive dichlorocarbene, due to competitive insertion of the carbene
通过在易于获得的3-亚烷基-1,2-二氮杂环丁烷的环外双键上通过二卤代卡宾加成制备4,5-二氮杂螺并[2.3]己烷。使用由TMSCF 3 / NaI生成的二氟卡宾,通过整个烯烃的立体有规加成,可产生高达97%的产率的螺环。使用更具反应性的二氯卡宾可观察到较低的收率(高达64%),这是因为卡宾竞争性地插入了N–N键。通过将3-亚烷基-1,2-二氮杂环丁烷与四氰基乙烯(TCNE)进行[2 + 2]环加成反应,可制得较大的1,2-二氮杂螺并[3.3]庚烷,产率高达99%。