200068-65-1Relevant articles and documents
A New Route to Sila- and Phosphaheterocycles: Nucleophilic Aminomethylation
Karsch, Hans H.,Schreiber, Kai-A.,Herker, Martin
, p. 1777 - 1786 (2007/10/03)
The aminals tetramethylmethylenediamine (TMMDA) 1a, dicyclohexyldimethylmethylenediamine (CMMDA) 1b, and diisopropyldimethylmethylenediamine (IMMDA) 1c are doubly metalated by LitBu to give LiCH2N(R)CH2N(R)CH2Li , which precipitate out of pentane as highly pyrophoric substances.Deuteration confirms N-methyl metalation exclusively.A series of aminomethylation reactions were performed by means of the doubly lithiated aminals 2a-c.The reactions of 2a-c with monochlorosilanes yield the silylated species R'3SiCH2N(R)CH2N(R)CH2SiR'3 (3a: R' = Me, R = Me; 3b: R' = Me, R = Cy; 3c: R' = Me, R = iPr; 4: R' = Ph, R = Me, see Scheme 2).The use of dichlorosilanes leads to six-membered heterocycles 6a-6d. 6a is transferred into a mono quaternary ammonium salt 7 by methylation with MeI.The spirocycle 8 is obtained from SiCl4 and two equivalents of 2a.Similarly, several substituted 1,3-diaza-5-phosphacyclohexanes 9a-e (R1 = Me, Ph, NPh2, NCy2, see Scheme 3) are synthesized by the reaction of dichlorophosphanes R1PCl2 with 2a and 2b, respectively.Oxidation of 9d with sulfur yields 12a, which is characterized by X-ray structure determination. - Keywords: Lithiation; Aminomethylation; Nitrogen heterocycles; Diazasilaheterocycles; Diazaphosphaheterocycles
