10urnal of Scientific & Industrial Research Vo1.59, April 2000, pp 265-279 Methods of Synthesis and Properties of 1-Vinylsilatranes* + M Nasim and PS Venkataramani Defence Materials & Stores Research & Development Establi shme nt, DMSRDE PO, GT Road, Kanpur 208 01 3 and G S Zaitseva Chemistry Department, M oscow State University, B-234, Vorob Evy Gory, 119899, M oscow, Russ ia The sy nthesis and chemical reactivity of I-vinylsilatranes have been reviewed. Chemical reactions of I-vi nylsil atranes such as cycloaddition, oxidation, hydrosi lylati on and derivatisation have been discussed in detail. Literature available/publi shed till the end of 1998 have been covered. 1 Introduction itself, the simplest compound of thi s class has structure II, where R= H, M =Si. The chemistry of organo compounds of IYB group elements (Si, Ge, and Sn) is one of the fascinating areas having practical utility l-4. Compared to th e organocompounds of silicon and tin , the l)2 ~~__ C!h organogermanium compounds are comparatively less H/Hi 1 H, studied and are not widely used in practice. This is be­ \4-A1- o I cause of relatively hi gh cost of the starting germanium R source such as germanium metal and its oxide. How­ ever, during recent years, spec ific and prospective prac­ (I) (11) ti cal applications of organogermanium compounds have been established in terms of its bi ological and pharma­ Figure I - (I) Depicts heterocyclic skeleton (M=metal) and (II ) cological activity3- JO. depicts si latrane (R= H, M=Si) Now-a-days intensive and useful research is being Metall atranes having cage structure are a class of carried out in the field of organo derivatives of sili con, pentacoordinated organometallic compounds formed germanium, and tin in which the metal atom present has from th e reacti on of trialkanolamines such as tri eth­ the coordination number differing from four. In the se­ anolamine with trifunctional si lanes, germanes or ri es of pentacoordinated compounds, a special pl ace is stannanes, [RM(OR)3]' These are characterized by occupied by the cyclic compounds of silicon, germanium transannular donation of electron density from nitrogen and tin derivatives of triethanolamine and its homol ogue to th e metal atom, thereby producing an effective 2Y 3 pentacoordination at sili con or germanium -32 called sil atranes2.11 -21, germatranes .4.22 and stannatranes 23- 26, respectively. In general, th ese compounds are classi­ Syntheses of new sil atranes are of mu ch interest in fied under "metallatranes" as proposed by Yoronkov et view of their interesting biologicaI2.:n-3\ physicochemi ­ ai. 27.2X. The chemical nomenclature is l-organyl-2,8,9- caP6-39 , and structural properti es 40-47 . Chemical investi­ trioxa-5-aza- l-metalla (s ila, germa, or stanna) tricyclo gati ons of these hypervalent sili con species are being 4x 50 [3.3.3.0 15] undecanes. intensively pursued - . Their heterocyclic skeleton is depicted in struc­ Silatranes are technologically important materials ture-I, where M stands for metal (Figure I). Silatrane in view of their potential applications in rodenti cides 'il , 34 in secti cides , crop yield enhancement3'i.'i2 , medicine (wound healing, intensification of hair growth-treatment *DMSRDE Reference No. 2528. of diffe rent kind of alopecia)2.35, agrochemicals + Author for correspondence. 266 J SCI INO RES VOL.59 APRIL 2000 (microbic ides, bactericides, fungicides and an ti cancer It became poss ib le for S amo ur ~() to synthes ize 1- agents)53-S\ polymers and compos ite materi als (curing vin yl-(3,7, I O-trimethyl)s il atrane (6) by the above meth od agents for a number of synthetic res in s, key in g coupling using triisopropanolamine (5). agents?.5fi.S7 , textiles (water and oil repellents)\ corro­ sion inhibitor2.5x.59 , seri culture (s ilk produ ction)35.oo, conservating agent (fish conservati onf. Silatranes are 2 of certain practi cal interest as suitable alkylatin g , 3 5 alkenylating2, arylating2 and reducin g agentsh l for th e CH =CHSi [OCH(CH )CH N + 3EtOH preparati on of very pure organi c deri vati ves of heavy 2 3 2J3 2 metals . 6 The practical application of sil at ranes are not lim­ However, in this method the reactants were sub­ ited. The combinati on of the sil atrane moiety with jected to prolon g heatin g for completi on of the reacti on. organometallics should be of interest whi ch can be used Addition of catalytic amounts of sodium or potassi um as redox potenti aP9 and also of technological importance alkox ide in the reacti on mi xture shortened th e reaction e.g. non linear opti c materi als21. Group 13 azatranes time. Thus, Voronkov et af. X2 sy nthesised compound 1 (azaalumatranes, azagall atranes) and group 14 azatranes and its C-methyl su bstituted (in the afrane cycle) ana­ (azas il atranes, azagermatranes etc) wi ll be futuristic po­ logue by th e transesterificati on of compound 2 wit h tential MOCVD agents fo r metal and non-met I nitrides tri s(2-alk anolamines) in th e pr sence of 10 per cent film precursorso2.o3 . meth anoli c so luti on of sodium meth oxi.de. Recently, we initiated in ves ti gating the sy nthesis + and chemical properties of functionali sed sil atranes4s -47.o4-69, and (McO),Si CH=CH, N(C H, CH,O H)"(CH,CHOH),.,, 7X 2 CH, I germatranes70- . A large number of fun cti onali zed 211 13 -- N(CH,CH,O)" (C H,CHO),."SiCH=CH, + 3MeOH sil atranes havin g become avail abl e in earlier years . • CH, I Our main attrac ti on was fo r l-vin ylsil atranes sin ce 7,8 in our hands th ese proved to be excell ent precurso r ma­ n = I (87 per celli) (7); n = 2 (85 per celli) (8) teri als for the synthesis of several new fun c; ti onli sed sil atranes. Thus the paper su mmari zes the numerou s data Intermolecul ar condensati on of si Iylether deri va­ avail able on I-vinylsil atranes, hi ghli ghti ng, both their tives of di oxaazasil ocanes (9-11) containing a phenyl preparati ve aspects as we ll as reacti vity. The literature group at sili con gave compound 1. Reaction proceeded up to the end of 1998 is covered here. onl y in the presence of sodium alkox ide to yield com­ pound 1 in 70-80 per cent yieJdK3. 2 Methods of Synthesis of 1-Vinylsilatranes I-Vinylsilatrane, N(CH CHP\SiCH=CH (1), was "ACH,CH2 . 2 2 , fir t prepared by Frye et af. 79 by transesterifi cation of RRIS( >-CH2CH20R2 + (AlKOhSiCH=CH --> OCH2CH2 vinyltri al koxysil anes (2, 3) with tri eth anolami ne (4). 9-11 Later, transesterification of Si-substituted tri alkoxys il anes was widely and successfull y used for R, RI = Me, R' = H (9); R, RI = -CH=:CHr R' = H (10), R = ­ the synthesis of I-vinylsil atranes and vari ous I-su bsti­ CH=CH" RI = Ph, R' = S iM e~ (11) tuted sil atranes2.".xo.x ,. It was observed that besides vin yl group, if phenyl group was present at the silicon of th e cycli c ether, mi ­ gration of phenyl group took pl ace under the influence (RO)3SiCH=CH2 + N(CH CHPH\ ~ 2 X3 2,3 4 of base giving ri se to product of sil atrane structu res . C H ~C H , OH N(CH,CH,O),SiCH=CH2 + 3ROH - - . S i (OC H , C H ,), NC H , C H ,oSiMc ~ ----~ 1 Ph/ - P h S i Me ~ R =: Me (2), R = Et (3) N(CH,CH,o),SiCH:=CH, NASIM & VENKATARAMANI: VINYLSILATRANES 267 The scope of trans esterification reaction is not lim­ 1- Vinyl-3-(2-vinyloxyethoxymethyl)silatrane (28) ited and the synthesis of various I-v inylsilatranes hav­ was obtained in almost quantitative yield by the acti on ing different substituents in the atrane fragment as well of compound 3 with N-[2-hydroxy-2-(2-vinyloxy­ as at alpha and beta carbon atoms of vinyl group have ethoxymethyl) ethylbis(2-hydrox yethyl ) amine] (27) at X7 been accomplished usin g this methodology. Thus, I-(a­ 20-40"C in the absence of catalyst • chloro-, ~-chloro- , ex, ~-dichloro- and ~ , ~ ' di c hlor o) X4 vinylsilatranes were obtained in 85-95 per cent yi eld s HN (CH,CH,OH), + CH,- CH-CH,OC H,CH,OC H=CH, by reacting the corresponding vinyltrialkoxysilanes with - -- ' 0 1 26 - -- compound 4. (RO\ SiC(X) = C (XI) (Xl ) + N ( CH I C HPH » ) ~ __-+. N"" (CH,CH,OH), N(CH lCHP »)SiC(X)=C(X I)( Xl) 3 ' CH;t HOH 12-15 CH,OCH,CH,OCH=CH, 27 X = XI= H, Xl= CI (93 per cent) (12); X = CI, XI = XI = H (90 per cent) (13); X= XI= CI , X~ H (92 per cent ) (14); X = H, XI = Xl = CI (85 per cent ) (15) Lower yields were observed in the case of I-(beta phenyl- and beta silyl)v inylsilatranesxs. A seri es of I-vinylsil atranes which were C­ I (RO»SiCH=CHR + N(CH2C HP H\ ~ trifluoromethyl substituted in the 3-position of atrane fragment were prepared in 45-99 per cent yields by N(CH2CH20»SiCH=CHRI + 3ROH transesterification of the corresponding vinyltrialkoxy­ 16-18 silanes with tri s(2-oxyalkyl)amines. The reacti on was R' = Ph (70.6 per cent) (16), SiMc) (83 per cent) (17), SiMelh carried out without solvent in the presence of 10 per cent (70.8 per cent) (18) methanolic solution of sodium m e thoxide xx.~' .