Phosphine reactions with aldehydes

Sulfonimidophosphonates Phosphides s. Alkali phosphides Phosphinaminoboranes 16, 374 Phosphine, reactions with aldehydes, aliphatic 16, 696 —, reductions with — 17, 346 Phosphine boranes... 

Issleib, Oehme, and Zschunke [72MI1 73ZC(13)291 78PS(5)81 79ZC57] obtained secondary phosphines with a y-oxypropyl substituent via the addition of primary phosphines to allyl alcohols and studied their reactions with aldehydes and ketones. Addition of carbonyl compounds proceeds without catalysts at room temperature and is accompanied by... 

A study of the kinetics and products of the thermolysis of a series of diaryl-phosphinic azides has been reported.119 Diethyl 1-diazomethylphosphonates undergo an aldol-type reaction with aldehydes to give l-diazo-2-hydroxyalkylphosphonates (152).120 Acidification of the diazophosphonates (153) possessing a chiral phosphorus centre yields mixtures of diastereoisomers (154) and epimers at C. For given R1 and R2, the reaction becomes increasingly stereoselective for X= OAc < Cl < OTs. It may be argued that protonation of (153) will yield a mixture of diastereoisomeric di-... 

Base-Catalyzed Reactions of Phosphonomethyl-phosphinates, Bis(phosphonomethyl)phosphinates, and Bis(phosphonomethyl)phosphinic Amides with Aldehydes... 

The nature of the substituents on a stabilized phosphonate carbanion is known to influence the stereochemical outcome of their reactions with aldehydes. For example, a bis(2,2,2-trifluoroethyl) substituent reverses the normal preference for (E) alkenes in a sequence referred to as the Still modification of the HWE reaction (see Protocol ll).24 This substituent is thought to favour formation of the (Z)-isomeric alkene by greatly enhancing the rate of the elimination of the phosphine oxide to give the alkene, which then suppresses equilibration to the thermodynamic product. 

N-acylaziridines occurs on treatment with triphenylphosphine with the formation of the ylides (67), thereby providing a route to a-substituted primary allylic amines via their in situ reactions with aldehydes.The reactions of triphenylphosphine with epoxides in phenolic media provide a new access to the vinyl-phosphonium salts (68). A route to 1-hydroxyalkylphosphonium salts is provided by the reactions of trimethyl- or triethyl-phosphine with aldehydes or ketones in the presence of anhydrous acids. The related 1-trimethylsiloxyalkylphosphonium salts can be isolated in the presence of trimethylsilyl chloride.Further Wittig-products have been isolated from the reaction of 1,2,3-indanetrione with triphenylphosphine, and, in related work, it has been shown that furoin is deoxygenated on heating with triphenylphosphine to form 2-furfuryl(2-furyl)ketone and triphenylphosphine oxide.The structure of the blue product from the reaction of triphenylphosphine with 2,3,5,6-tetracyano-7-oxabicyclo(2,2,1]hepta-2,5-diene has now been shown by X-ray techniques to be the stable ylide (69). ... 

Lithium derivatives of amino substituted phosphine oxides, such as the morpholine 121, give adducts 122 on reaction with aldehydes that eliminate with a potassium base to give enamines 123 in excellent yields 90-99% for R = Ar and 63-83% for R = alkyl. These are easily hydrolysed to the homologous aldehydes27 124. 

Ring strain makes trimethylsilylcyclopropenes susceptible to attack by Ar3P such that further reaction with aldehyde is realized. A Brook-type rearrangement drives the reaction to completion by expulsion of the ArsP from the adducts. In practice, tris(2,4,6-trimethoxy-phenyl)phosphine is used instead of Ph3P (much better yields). ... 

The reactions of dialkyl phosphonates and secondary phosphine oxides with aldehydes have been used to prepare ct-hydroxyalkylphosphonates and various a-functionalized tertiary phosphine oxides. In contrast to previous reports, dialkyl phosphonates have been shown to react exothermically with benzophenone in the presence of base to give... 

Polymer-bound triphenylphenylphosphine [354] has been converted to a phosphonium salt 8i by reaction with 2-nitrobenzyl bromide. The nitro group was then reduced to an amine and acylated. The resulting product formed a resin-bound ylide in the presence of base, which underwent a Wittig reaction with aldehydes that released alkenes into solution with the phosphine oxide by-product remaining bound to the solid support [355]. 

A proposed reaction pathway by which ammonia is formed is shown in Scheme 6. After the dissociation of phosphine, attack by another hydrazido complex (e.g., A) to form a bridged species, C, is proposed. Hydrazido complexes such as A are known to be good nucleophiles. For example, they react in acid catalyzed reactions with aldehydes and ketones to form diazoalkane complexes (e.g.. Equations 4 and... 

In the proposed mechanism, the iron porphyrin serves to catalytically convert the diazo reagent and phosphine to the corresponding phosphorane. Then, the phosphorane produces a new olefin and phosphine oxide on reaction with aldehyde [196]. Although other metal complexes can catalyze this reaction [ 197,198] the iron system seems to be especially efficient. 

Phosphonium ylids undergo a most important reaction with aldehydes and ketones, known as the Wittig reaction (3.111). The products of this reaction are olefinic compounds and phosphine oxides. 

Reaction with aldehyde to phosphonium salt adducts containing 2 or 3 mol aldehydes/mol phosphite. Reaction widi water gives a-hydroxyaUcyl-phosphinate esters, acetal phosphonate, and eventually phosphinic acids [19, 21] (see Chapter9). 

The titanium- ate complexes of a-methoxy allylic phosphine oxides, generated in situ by reaction of the corresponding lithium anion and Ti(0-i-Pr)4, condense with aldehydes exclusively at the a-position to produce homoallylic alcohols in a diastereose-lective fashion. The overall result is the three-carbon homologation of the original aldehyde, and this protocol has been used in a synthesis of (-)-aplysin-20 from nerolidol. The titanium- ate complex produced by reaction of the chiral lithium anion of an ( )-crotyl carbamate with Ti(0- -Pr)4 affords -y-condensation products (homoaldols) on reaction with aldehydes. Allyl anions produced by the reductive metalation of allyl phenyl sulfides condense with a,p-unsaturated aldehydes in a 1,2-manner at the more substituted (a) allyl terminus in the presence of Ti(0-i-Pr)4. 1,2-Addition of dialky Izincs to a,p-unsaturated aldehydes can be achieved with useful levels of enantiocontrol when the reaction is conducted using a chiral titanium(IV) catalyst in the presence of Ti(0- -Pr)4 (eq 20). Higher ee values are observed when an a-substituent (e.g. bromine) is attached to the substrate aldehyde, but a -substituent cis-related to the carbonyl group has the opposite effect. 

---