Tatsuzo Ukita

Stereochemistry of an oxidative 1,4-fragmentation of γ-stannyl alcohols with a hypervalent organoiodine compound and the synthesis of erythro-6-acetoxyhexadecan-5-olide

Iodine(III)-mediated oxidative 1,4-fragmentation of the 2,3-trans- and 2,3-cis-3-stannyl alcohols, (6a,b) and (6c), proceeds stereospecifically to give the E- and Z-enals, (7) and (8), respectively, and stetreoselective synthesis of the mosquito pheromone, erythro-6-acetoxyhexadecan-5-olide (5), starting from the E-enal(7), was accomplished.

A new desulphonylation of α,β-unsaturated sulphones via conjugate addition of tributylstannyl-lithium

α,β-Unsaturated sulphones (1) on treatment with tributylstannyl-Lithium in tetrahydrofuran at –78 °C, give the Michael type addition products, β-tributylstannyl sulphones (2), and their successive β-elimination by reaction with silica gel affords the desulphonylated olefins (3) in good yields.

1,4-Fragmentatioin of γ-tributylstannyl alcohols by a hypervalent organoiodine compound: a new synthesis of unsaturated carbonyl compounds

1,4-Fragmentation of γ-tributylstannyl alcohols using iodosylbenzene, boron trifiluoride–diethyl ether, and dicyclohexycarbodiimide produces unsaturatd carbonyl compounds; the fragmentation, combined with conjugate addition of tributylstannyl-lithium and reduction or alkylation, offers an efficient procedure for the reductive and alkylative ring opening of cyclic vinyl ketones.