150112-33-7Relevant academic research and scientific papers
Contributions to the Chemistry of Boron, 217.- Cycloaddition Reactions of 9-Fluorenylidene(tetramethylpiperidino)borane with Carbonyl and Thiocarbonyl Compounds
Channareddy, Sreelatha,Glaser, Bernd,Mayer, Erwin P.,Noeth, Heinrich,Helm, Scott W.
, p. 1119 - 1126 (2007/10/02)
Amino-9-fluorenylidene-borane 1 reacts with acetone or benzophenone in a cycloaddition manner to give stable 1,2-oxaboretane derivatives 2.Aldehydes behave similarly but the oxaboretanes formed decompose readily.The esters MeCO2Et and MeCC-CO2Me as well as Cp(CO)2Fe-COCH3 also provide access to novel oxaboretane derivatives (2e,f,h).In contrast, no oxaboretane is obtained from 1 and MeC(O)NMe2 and only (tmpBO)n (n = 2,3) was isolated as a decomposition product.The amides MeC(O)NHMe and MeC(O)NH2 also provide no access to cycloaddition since their NH bonds insert into the BC double bond of 1.Thioketones react with 1 to yield 1,2-thiaboretanes 5.Tetramethyl-cyclobutan-1-one-3-thione 8 adds 1 at its carbonyl function regiospecifically to form 9.No reaction between 1 and CO2 was observed, but COS produces an 1,2-oxaboretane-4-thione 7, and CS2 in the form of 2CS2 the corresponding 1,2-thiaboretane-4-thione 10.Analogously, the ketimine Ph2C=NMe adds to 1 producing the 1,2-azaboretidine 11.X-ray structure determination of the 1,2-oxaboretane 2h reveals a butterfly structure (folding angle: 159.9 deg) of the four-membered ring in contrast to the 1,2-thiaboretane 5a whose four-membered ring is almost planar, the folding angle being 176.9 deg.Key Words: Cycloaddition reactions / 1,2-Oxaboretanes / 1,2-Thiaboretanes / 1,2-Azaboretidines
