Organometallic compounds organosilanes

Acetals prepared from chiral diols and carbonyl compounds serve as a chiral synthetic equivalent of aldehydes or ketones. 1,3-Dioxanes synthesized from chiral 2,4-pentanediols are especially useful, and high asymmetric inductions are observed in the Lewis acid promoted reactions of a variety of organometallic compounds. After the removal of the chiral auxiliary by the oxidation and -elimination procedures, optically active alcohols are obtained. Optically active propargylic alcohols and cyanohydrins are synthesized from organosilane compounds, TMS-C CR or TMS-CN in the presence of TiCU (Scheme 24). 1 6-138 Reactive wganometals such as alkyl-lithiums, -magnesiums or -coppers also react with chiral... 

The application of the MW technique to main group organometallic compounds was pioneered by McWhinnie and his co-workers, and some specific examples are given in Scheme 12. More recently, the technique has been used in the synthesis of organosilanes and germanes, and the method has been applied to accelerate the synthesis of aryl Grignard reagents. 

The preparation of a large number of unsymmetrical tetraorganosilanes includes reaction of certain Si-functional organosilanes with organometallic compounds and the hydrosilation of unsaturated hydrocarbons. Table 3.1 presents typical examples of the preparation of unsymmetrical tetraorganosilanes from Si-functional organosilanes and organometallic compounds. 

Organosilane Organometallic compound Reaction conditions Tetraorgano- silane Yield % b.p. (m.p.) °C Ref. 

The fluorination of organometallics with Al-fluoroamide reagents has received Only limited attention. Grignard reagents, both aliphatic and aromatic, are converted to organofluonne compounds. Both the electron transfer and the Sf,j2 ntechamsms have been considered in these processes [SO, 81, 82], The reactions 0 exemplified in equation 46 [48, 69, 70, 71, 75] Organosilanes are also fluonnated [71] (equation 47)... 

Chemical methods are generally based on the reaction of surface hydroxyl groups with a selectively reacting compound to form a covalently bonded surface species of well known composition. As reactive compounds, diborane,4,5 boron trichloride,6,7 diazomethane,8 organosilanes,3,6,9,10,11,12,13,14 and organometallic compounds15 have been employed. a0H is then derived from the amount of the chemisorbed species as well as the amount of volatile reaction products. 

Comprehensive Organometallic Chemistry Pergamon New York, 1982, Vol. 2. Chapters on Organopolysilanes , Carbocyclic Silanes , Organosilanes , and Silicon Compounds in Organic Synthesis (Vol. 7) by R. West, T. J. Barton, D. A. Armitage, and P. D. Magnus, respectively. 

The two most general means of synthesis of organosilanes are nucleophilic displacement of halogen from a halosilane by an organometallic reagent and addition of silanes at double or triple bonds (hydrosilation). Organomagnesium and organolithium compounds... 

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