Reaction with hydride reagents

The reduction of carbonyl compounds by reaction with hydride reagents (H -) and the Grignard addition by reaction with organomagnesium halides (R - +MgBr) are examples of nucleophilic carbonyl addition reactions. What analogous product do you think might result from reaction of cyanide ion with a ketone ... 

Although deoxy sugars can also be formed directly from triflates by reaction with hydride reagents [Eq. (9) 19], molecular rearrangement [Eq. (10) 20] sometimes accompanies this pathway.)... 

Formation of an Alcohol The simplest reaction of a tetrahedral alkoxide intermediate is protonation to yield an alcohol. We ve already seen two examples of this kind of process during reduction of aldehydes and ketones with hydride reagents such as NaBH4 and LiAlH4 (Section 17.4) and during Grignard reactions (Section 17.5). During a reduction, the nucleophile that adds to the carbonyl... 

Vis and Karrer114 have found that treatment of methyl 4,6-O-benzyl-idene-2,3-O-p-tolylsulfonyl-a-D-glucoside (13) with lithium aluminum hydride provides methyl 4,6-0-benzylidene-3-deoxy-a-D-n 6o-hexoside (IS) in good yield. Since hydrogenolysis is possible at both C-2 and C-3 of the two possible 2,3-anhydro derivatives, only the alio isomer (14) could give the 3-deoxy derivative by further reaction with a reagent. Indeed, none of the alternative 2-deoxy derivative was found. This transformation is, un-... 

Most efforts to explore the reactivity of ruthenium carbene complexes have employed the alkoxycarbene species so readily synthesized from the inter- or intramolecular reaction of vinylidene complexes with alcohols. These electrophilic alkoxycarbene complexes exhibit only limited reactivity at Ca, primarily with hydride reagents. For example, treatment of the 2-oxacyclopentylidene complex 97 with NaAlH2(OCH2CH2OMe)2 affords the neutral 2-tetrahydrofuranyl complex (98) [Eq. (89)] (55), as was anticipated from similar reductions of iron carbene complexes (87). 

Reactions with Nucleophilic Reagents In close parallel with the oxidation of tropilidene derivatives by tropylium salts,81 for example, 1,2-dithiolium salts containing a single substituent in position 4 or 5, e.g. 70, can capture a hydride anion from the doubly substituted, highly strained leuco bases (71), thus oxidizing the latter to the more highly substituted and thermodynamically more stable salts (73).82... 

The reaction of tt -allyl palladium complexes with hydrogen causes decomposition of the compounds, and produces either alkenes or alkanes, depending on the degree of substitution of the TT-aUyl complex and the reaction conditions. Hydride reagents, such as NaBUi and LiAUTi, also reduce the aUylic group to alkanes or alkenes. 

Hydride donors, such as LiAUTi or NaBH4, will cleave Pd bonds, including those in cyclometalated complexes. If the molecule contains groups that will react with hydride reagents, the same transformation can be carried ont nsing H2 (eqnation 79). This reaction has been nsed with LiAlD4 to establish the precise position of metalation. 

Alkyne ligands are susceptible to attack by nucleophiles, which typically leads to the formation of -vinyl complexes " this is particularly true in the case of electron-deficient alkynes. Noteworthy in this regard are the reactions of [Tp W(C0)2( ] -RC=CR )]+ cations with hydride reagents that yield )) -vinyl, ) -allene, or ry -alXyX complexes depending upon the nature of the alkyne substituents." ... 

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