Aluminums stannyl

The most general way to obtain chiral a-stannylated ethers today consists of the asymmetric reduction of acylstannanes34,35,36 using the 2,2 -dihydroxy-l,T-binaphthyl-modified lithium aluminum hydride (BINAL-H) reagent37 and etherification of the crude alcohol with chloro-methoxymethane. 

When dienones such as 55 are subjected to the epoxidation conditions the electron-poorer C=C double bond is selectively epoxidized. The other C=C bond can be functionalized further, for example, it can be dihydroxylated, as shown in the synthesis of the lactone 56 (Scheme 10.11) [82]. Stannyl epoxides such as 57 (Scheme 10.11, see also Table 10.8, R1 = n-Bu3Sn) can be coupled with several electrophiles [72], reduction of chalcone epoxide 58 and ring opening with alkyl aluminum compounds provides access to, e.g., the diol 59 and to phenylpropionic acids (for example 60). Tertiary epoxy alcohols such as 61 can be obtained with excellent diastereoselectivity by addition of Grignard reagents to epoxy ketones [88, 89]. 

Lithium tetrakis[methyltelluro]aluminate, prepared from methanetellurol and lithium aluminum hydride, reacted with silyl, germyl, and stannyl halides at low temperatures to produce, for instance, methyl silyl tellurium derivatives1. 

HOMOALLYLIC ALCOHOLS B-Allyldiisopino-campheylborane. Allyl phenyl selenide. Allyltri-/i-butyltin. Chromium(II) chloride. Crotyltrimethylsilane. Diethylftributyl-stannyl)aluminum. (2R,4R)-Pentanediol. Pinacol chloromethaneboronate. Tin-Aluminum. Titanium(lV) chloride. 

Anionic nucleophiles provide valuable and versatile routes for the preparation of C-glycosides. However, the most extensively used technologies lie within the chemistry of Lewis acid-mediated reactions of carbohydrates with unsaturated hydrocarbons and derivatives thereof. In the next series of examples, reactions of sugars and sugar derivatives with olefins and their silyl-, stannyl-, and aluminum derivatives are discussed. 

The preparation of enantioenriched Q -(alkoxy)allylstannanes has been advanced by the asymmetric Noy-ori reduction of the stannyl ketone 264 with 2,2 -dihydroxy-l,T-binapthyl lithium aluminum hydride (BINAL-H) reagents affording the non-racemic (5 )-265 with > 95% ee, upon O-alkylation with common protecting groups (Scheme 5.2.57, top). °... 

An early contribution to use of the transition-metal-catalyzed pyridine formation reaction was the synthesis of vitamin Be (124) via the crossed-cyclotrimerization reaction of the bis-stannylated diyne 122 with acetonitrile under cobalt catalysis (Scheme 7.26) [36a andb]. The underlying crossed [2 - - 2 - - 2] cycloaddition reaction here provided the fused pyridine 123 in 76% yield after a regioselective destannylation effected by treatment of the cycloaddition product with aluminum oxide. 

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