Crystal structure of ethyl (-)-(1S,2R,5S,7S,8R,4'S,5'S)-2-methoxy-8-(2' ,2'- dimethyl-5'-phenyl-1',3'-dioxolane-4'-yl)-6-oxo-tricyclo[3.2.1.02.7]octane-1-carboxylate, C23H28O6

Synthesis and Anionically Induced Domino Reactions of Chiral α-Bromo α,β-Unsaturated Esters

“…The geometries of the α,β-bonds [(Z)/(E)] in 3 and 6 were (a) Esters of Type 3: Both the chiral (Z)-α-bromo α,β-determined by measuring the 3 J( 13 C, 1 H) coupling constants unsaturated ester 3a [6] and the prochiral α-bromo α,β,γ,δ-(carbonyl-C and β-H), typical values for which are around unsaturated esters 5 are available by Wittig olefination 4.8 Hz for (Z)-and up to 12 Hz for (E)-diastereomers (see from (ethoxycarbonyl)bromomethylene-triphenylphosphoalso Table 3). [8] Similar compounds such as 2 (R ϶ H) are rane (1) [7] and the appropriate aldehydes 2 (R ϭ H, derived not available in the chiral pool, but can be made by Sharpfrom -mannitol) and 4, respectively (Scheme 2).…”

“…The chiral (Z)-ester 3a reacts with high diaselectivity of the AD-mix α or β, respectively) were predicted with the "mnemonic device" suggested by Sharp-stereoselectivity (de Ն 95%) to afford enantiopure tricyclo[3.2.1.0 2,7 ]octane 11a-Me. [18] The homologous esters 3b less [11] and later proven by the subsequent transformations leading to the crystalline tricyclic compound 11c-OMe [12] . and 3c behave similarly and form with the dienolate Li-10 single adducts 11b, c (Scheme 4, Table 1).…”

“…Clearly, the adThe corresponding (Z)/(E)-7-Cl, -I, however, were obtained by a "one-pot" Horner-Emmons olefination/hal-ditional (S)-configured stereogenic center at C-5 of the di- strongly supported by the X-ray structure of 11c-OMe. [12] 940, 865, 815, 760. Ϫ UV/Vis (methanol): λ max (lg ε) ϭ 209 nm…”