ISSN:
0947-3440
Keywords:
Asymmetric synthesis
;
Homogeneous catalysis
;
Hydroformylations
;
Rhodium
;
Catalyst-directing group
;
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The development of an efficient catalyst-directing group based on ortho-diphenylphosphanyl benzoate (o-DPPB) for the substrate-directed, diastereoselective hydroformylation of methallylic alcohols 5 is described. The hydroformylation of methallylic o-DPPB esters 9 provides the corresponding syn-aldehydes 10 with diastereoselectivities of up to 96:4. A specific steric demand of the substituent at the stereogenic center of the methallylic derivatives 9 was found to be necessary to achieve a high degree of stereoselectivity. Experiments have been performed that prove that the o-DPPB group acts as a catalyst-directing group by reversibly coordinating to the catalyst. The removal of the o-DPPB group was accomplished by means of alkaline hydrolysis, thereby furnishing the lactols 6. Oxidation of 6 provides the corresponding γ-lactones 7.
Additional Material:
3 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jlac.199719970907
