Prostaglandins and congeners I. The synthesis of 11,15-bisdeoxyprostaglandins E1, E2, and F1α. The stereospecific conjugate addition of a lithium -1-alkenylalanate.

Stereospecific Conjugate Alkenyl Group Transfer to α,β-Enones Using Vinylalane Reagents

“…It has also been observed that trans-vinyl Al "ate" complexes react with conjugated ketones to transfer only the vinyl ligand in a 1,4-manner and the trans-stereochemistry is retained (24). Since this reaction is applicable to transoid enones, it complements the results described here for vinylalanes.…”

Prostaglandins and congeners. 21. Synthesis of some cyclohexyl analogs (11.alpha.-homoprostaglandins)

“…Ethyl 9-Oxo-l la-homo-13-trans-prostenoate (10). To a stirred solution containing 72 mmol of diisobutyl-íran,s-1 -octenylalane1" in 15 mL of benzene and 35 mL of ether at 0 °C was added 41 mL of 1.6 M methyllithium in ether.…”

“…For the preparation of 11,15-dideoxyprostaglandins, of interest as specific prostaglandin antagonists,9 the conjugate addition of lithium trialkyl-ímns -1 -alkenylalanates to cyclopentenones has been a particularly useful procedure.10 Reaction of alanates 8 and 9 with cyclohexenone 6 by this method gave the desired conjugate addition products 10 and 11, which were saponified to the corresponding acids 12 and…”

Stereochemistry of 14,22-ethers formed by cyclization of .DELTA.7-22-hydroxy steroids

“…The residue was separated by preparative TLC on 10% AgNOg-silica gel (solvent: 10% ether-hexane), giving 4b4 (35 mg) and 4a (90 mg) crystallized from CHClg-MeOH as prisms: mp 136-138 °C; NMR b 0.91 (s, 3, 19-Me), 1.08 (s, 3, 18-Me), 4.94 (br m, 1, Wxp = 10 Hz, 3«-H), 5.09 (br s, 1, WU2 = 3 Hz, 15-H), 5.24 (m, 2, C-22,23 H), 7.4 (m, 3), 8.03 (m, 2); mass spectrum, m/e (relative intensity) 504 (1.7), 503 (3.9), 502 (M+, 8.2), 501 (1.3), 487 (8), 403 (11), 378 (42), 377 (100), 255 (34), 254 (26), 241 (13). 161 (17), 149 (10). 147 (30), 133 (11), 125 (11), 107 (17), 105 (23), 95 (11), 93 (14).…”