Scheme 9 summarizes the reaction of 2,5-dihdyrofuran, 3-pyrroline derivative and 4,7-dihdyro-1,3-dioxepin derive using chiral Rh-complex bearing R,S-BINAPHOS. The optically active aldehydes are obtained as single products with enantioselectivities between 64-97%. In case of 2,5-dihydrofuran, up to 64% regioselectivity is observed for the formation of tetrahydrofuran-3-carbaldehyde A , while the reaction of 2,3-dihyrofuran led to the formation of a mixture of A and B (1:1) with an ee of 38% in A.

Scheme 9

9.1.5 Reaction of Bicyclic Alkenes

The asymmetric hydroformylation of bicyclic alkenes has received little attention. This reaction is interesting because of the following features: (i) the reaction can lead to the formation of three chiral centers upon one C-C bond formation; (ii) there is no regioselectivity problem; (iii) functional groups located opposite to the carbon-carbon double bond could be versatile. Scheme 10 summarizes some of the examples for the asymmetric hydroformylation of bicyclic alkenes employing Rh-TangPhos.

Scheme 10