Synthesis of steroidal 3,5-dieno[3,4-b]dithianes

1,4-Dithianes: attractive C2-building blocks for the synthesis of complex molecular architectures

“…The direct dehydrogenation of 1,4dithiane is somewhat cumbersome [25], and, moreover, 1,4dithiane (1) is surprisingly not available in large quantities at a reasonable cost, in spite of its apparent simplicity. Our lab has found that the synthetic method for dihydrodithiins pioneered by Parham and co-workers to be the most suited (Scheme 4, 12 → 2) [28][29][30]. Parham described a ring expansion of 1,3-dithiolanes derived from α-halocarbonyls into the 1,4-dithianes which then dehydrohalogenate to afford dihydrodithiins.…”

Dithiaaromatic systems. II. Thieno[3,2-c] - and thieno[2,3-c]thiapyrylium perchlorates

“…Several other syntheses of dihydro-p-dithiins are known in which an ethylene thioketal is either the starting material or a possible intermediate. [6][7][8] The common feature of each of these reactions is that the position a to the original carbonyl carbon atom may develop electrophilic character by loss of acetate ion6 or chloride ion6•8 or by opening of an epoxide ring.7…”

“…Org. Chern., 32, 1558(1967. (9) The HMO calculations were carried out as already described* using the parameters ag = a + 0.90 and 0cs == 0.60 for both sulfur atoms, in order to be consistent with our previous calculations.8,8 (10) This compound (2) was also prepared in this laboratory essentially as described by Degani.4 Our sample {Anal.…”