(±)- Valeranone 0-15°c,10 1: 1 mixture of diastereomers Separated after photolysis DIBAL-H TsOH 4: 1 mixture Seperable mixture Epi-valeranone Takeshita, H. et al. Bull. Chem. Soc. Jpn. 1993, 66, 2699 Studies toward Cytochalasin C le Base Oxidation state crucia Me hv(254 nm), MeCN rt. 40 min 3.7:1.0 Fuchs, P- L, et al J. Org Chem. 1982, 47, 3121. 36A-06 handout3/31/001:35PMH (±)-Valeranone Takeshita, H. et al. Bull. Chem. Soc. Jpn. 1993, 66, 2699. Me Me O Me Me O O O Me H Me O O Me Me O Me Me O O TsOH 61% hν, Pyrex, MeCN/acetone (9:1), 0-15 o C, 10h H O O Me Me OH Me Me Me Me O O 1) DIBAL-H 2) TsOH 98% 50% Seperable mixture α:β 3:2 Me Me O Four steps 74% 1:1 mixture of diastereomers. Separated after photolysis. 4:1 mixture Valeranone:7-Epi-valeranone 7 Studies toward Cytochalasin C Fuchs, P.L., et al. J. Org Chem. 1982, 47, 3121. O EtO Me O O Br Seventeen steps 17% O O Me S O Me Me Me O O O Me Me Me Me O SO2 H H O O O Me Me Me Me O SO2 H H O hν (254 nm), MeCN, rt, 40 min 94% Oxidation state crucial O O Me Me Me Me O SO2 H H O Base O O 3.7 : 1.0 Me Me OH H NH H Bn Me OH O Me O OAc Cytochalasin C 36A-06-Handout 3/31/00 1:35 PM