Hydroxy ketones and 2-ketoaldehydes undergo indium mediated highly diastere
oselective mono and bis-allylation reactions to give respective 1-allyl 2a-
c and 1,2-bis (allyl)- 7a-c 1,2 diols. 2a undergoes I-2 / NaHCO3 and m-CPBA
mediated diastereoselective intramolecular cyclizations to provide respect
ive (2S*, 3R*. 5S*)-2,3-diphenyl-4-hydroxy-5-iodo methyltetrahydrofuran 4a
and (2S*, 3R*, 5R*)-2,3-diphenyl-4-hydroxy-5-hydroxymethyl tetrahydrofuran
5b as major product.