Regioselective hydroformylation allyl alcohols

In a similar fashion, allylboronates can be used as allylation reagents under hydroformylation conditions. Thus condensed 1,5-oxazadecalin systems are achieved via tandem hydroformylation/allylboration/hydroformylation sequences starting from an N-allyl-y-amidoallylboronate (Scheme 23) [77,78]. The aldehyde obtained from a regioselective hydroformylation undergoes diastereoselective intramolecular allylboration to give an intermediate al-lylic alcohol derivative. The reaction does not stop at this stage, since this... 

The hydroformylation of allylic alcohol 97 usually a mixture of regioisomers 98, 99, and propanal (for R=H) which is formed by the isomerization of the double bond and is subsequent fautomerism (Figure 29). The regioselectivity is mainly determined by the ligand. The substitution of the double bond also has a strong influence on the selectivity and reactivity. 

Several attempts are described in the hterature to conduct n-regioselective hydroformylation of allyl alcohols (Scheme 4.33) [68, 69]. A main target is 4-hydroxy-butyraldehyde (HBA). The product can be utilized as a precursor to 1,4-butanediol (BDO) [70]. The formation of the branched aldehyde is occasionally associated with the appearance of C3 side products, such as... 

The synthesis began with Yb(OTf)3-catalyzed oxymercuration [88] of ho-moallyUc alcohol 204 [89], prepared by asymmetric allylation with Brown s reagent, to generate organomercury chloride 205. Rh(I)-catalyzed formy-lation [90] of 205 in the presence of DABCO (0.5 equiv.) furnished aldehyde 206. Stereoselective crotylation of 206 via Brown s reagent, followed by regioselective Rh(I)-catalyzed hydroformylation provided lactol 203. Dia-... 

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