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A Surprisingly Stable 1‐(Chlorosilyl)‐2‐phosphaethenyllithium Compound, RCl 2 SiC(Li)=PMes*
Author(s) -
Cretiu Nemes Gabriela,
Ranaivonjatovo Henri,
Escudié Jean,
SilaghiDumitrescu Ioan,
SilaghiDumitrescu Luminita,
Gornitzka Heinz
Publication year - 2005
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.200400595
Subject(s) - chemistry , lithium (medication) , toluene , medicinal chemistry , derivative (finance) , cycloaddition , methanol , hydrolysis , inorganic chemistry , organic chemistry , catalysis , medicine , financial economics , economics , endocrinology
RCl 2 Si–C(Li)=PMes* ( 1 ) (R = 9‐methylfluoren‐9‐yl, Mes* = 2,4,6‐tri‐ tert ‐butylphenyl), considered as a key intermediate in the synthesis of the heteroallene RClSi=C=PMes*, was obtained from RCl 2 Si–C(Cl)=PMes* by lithium/chlorine exchange with n BuLi and evidence for its identity was obtained by hydrolysis. Remarkably, however, it failed to undergo a lithium salt elimination to form the corresponding chlorophosphasilaallene, RClSi=C=PMes*, even under prolonged heating in toluene. As shown by theoretical studies (RHF/3‐21G* and RHF/6‐31G**//RHF/3‐21G* level), interactions between the lithium ion and the π‐systems of the substituents at the phosphorus and silicon atoms could partly account for this stability. The lithium compound 1 reacts with methanol or chlorotrimethylsilane leading to new silylphosphaalkenes. The reaction of the lithium derivative 1 with benzaldehyde gave a four‐membered heterocycle with an exocyclic P=C bond which virtually corresponds to the product of a [2+2] cycloaddition between the Si=C and C=O double bonds. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)