The first exclusive regioselective fragmentation of primary ozonides controlled by remote carbonyl groups on ozonolysis of norbornene derivatives and reaction of final ozonides with triethylamine as a new probe for determining the regiochemistry of carbonyl oxide formation from primary ozonide fragmentation are reported. Ozonolysis of the endo adducts 3a-d and the deuterated compounds 8a and 8b in CDCl(3) at -78 degrees C gave the final ozonides 4a-d, 9a, and 9b as the sole products (>95%), respectively. No detectable amount of the isomeric final ozonides 5, 10, 11, and 12 was obtained. A mechanism is proposed to account for the exclusive regioselective fragmentation of the primary ozonides. Ozonolysis of 3a-d, 8a, and 8b in CH(2)Cl(2) at -78 degrees C followed by treatment with triethylamine exclusively gave the convex tetraquinane oxa cage compounds 16a-d, 19a, and 19b in 85-90% yields, respectively. No detectable amount of the other regioisomers 17a-d, 20a, and 20b was obtained. Ozonolysis of 3a-d, 8a, and 8b in CH(2)Cl(2) at -78 degrees C followed by reduction with dimethyl sulfide gave the tetraacetal tetraoxa cage compounds 21a-d, 23a, and 23b in 85% yields, respectively. The difference in function between triethylamine and dimethyl sulfide in reaction with final ozonide is demonstrated. Ozonolysis of the endo adducts 24a and 24b in CDCl(3) at -78 degrees C exclusively gave the final ozonides 27a and 27b, respectively. The order of the preference of various remote carbonyl groups to control the fragmentation of the primary ozonides formed by ozonolysis of norbornene derivatives is investigated. Ozonolysis of the endo esters 32a-c in CH(2)Cl(2) at -78 degrees C followed by reduction with dimethyl sulfide gave the new tetraacetal oxa cages 35a-c, with an alkoxyl group directly on the skeleton, and the novel triacetal oxa cages 36b and 36c, respectively. The structures of triacetal oxa cages are proven for the first time by X-ray analysis of the crystalline compound 36c.

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A neutralizing agent is usually employed to counteract the pH reduction during lactic acid fermentation by Rhizopus oryzae. Calcium carbonate (CaCO 3 ) is used as such a pH controlling agent. The low solubility of CaCO 3 in the fermentation broth could however lead to low efficiency in pH control and cause problems in the subsequent purification process. Therefore, an alternative agent in place of CaCO 3 was examined in this study. The effect of four different neutralizing agents, including CaCO 3 , sodium hydroxide (NaOH), ammoniacal solution and sodium bicarbonate (NaHCO 3 ) on lactic acid production and the morphology of the pellets were investigated. Results indicated that CaCO 3 was still the preferred choice, because of the pellet morphology and the highest lactic acid concentration (43.3 g/L) obtained in the batch using 60 g/L of sweet potato starch as feedstock. It is noteworthy that the lactic acid purification is relatively easier when using NaHCO 3 instead of CaCO 3 , due to the higher solubility of sodium lactate than calcium lactate. Therefore, even the batch with CaCO 3 had a slightly higher productivity (1.23 g/L/h) than the batch with NaHCO 3 (1.14 g/L/h), NaHCO 3 might be the first choice for process designers whenever recovery is vital.

The synthesis of alkyl-substituted pentaoxa[5]peristylanes has been accomplished by ozonolysis of 2,3-bis-endo-7-anti-triacylnorbornenes 6a-d and by direct chemical transformation of the tetraacetal tetraoxa cages 11 and 12. Various reaction conditions have been used to optimize the overall yield for the synthesis of methyl group substituted pentaoxa[5]peristylane 7d. Ozonolysis of 6d in CDCl(3) at -78 degrees C without reduction was performed to study the ozonolysis chemistry of the triacylnorbornenes 6a-d. The synthesis of the parent (unsubstituted) compound 25 of pentaoxa[5]peristylane has been accomplished by a three-step efficient sequence with a maximum 45% overall yield via ozonolysis of the dihemiacetal 24. The structure of pentaoxa[5]peristylanes was proven by X-ray analysis of the parent compound 25. The syntheses of the triacetal tetraoxa cage 26, a new type of oxa cage, and a new entry for the synthesis of the parent compound 33 of tetraacetal tetraoxa cages were also demonstrated.

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