Synthesis and characterization of 4-dimethylamino--triphenylmethylpyridinium chloride, a postulated intermediate in the tritylation of alcohols

Synthesis of model BC bicycles of taxol using C10–C11 ring-closing metathesis strategy

“…The primary alcohol of known optically active diol 13 8 was protected as its trityl ether. 9 Other protecting groups such as triisopropylsilyl (TIPS) or p-methoxybenzyl (PMB) ethers were also installed, but the yield of coupling between 9 and 12 revealed very dependent on this protecting group. We had originally planned to convert ketone 14 into vinyl bromide 12 by treatment of the corresponding hydrazone with NBS, 10 but formation of the hydrazone is plagued by an important quantity of azine.…”

<b>A solvent free and selective method for preparation of triphenylmethyl ethers of alcohols and nucleosides</b>

“…79-81 °C; R f[(EtOAc:n-Hexane) 2:8] = 0.6. 1 H NMR δ 7.49-6.91 (23 H, m, Ph-), 5.36 (1H, s, CH-), 3.77 (6H, s, CH 3 -).…”

“…In general, the sterically least hindered alcohols are the most readily tritylated. A large number of tritylation methods exist for the introduction of the trityl group into a variety of alcohols [1][2][3][4][5][6][7][8][9][10]. Due to its steric hindrance, trityl group finds a specific application and can be used for selective protection in different substrates such as selective protection of hydroxyl groups in nucleosides.…”

Total Synthesis of Brevetoxin A: Part 3: Construction of GHIJ and BCDE Ring Systems

“…Engagement of the two hydroxyl groups branching from ring D as a ketal with cyclohexanone dimethylketal and PPTS, furnished compound 74 (87 % yield) which was treated with PivCl and 4-DMAP to afford 75 (100 % yield). Cleavage of the ketal with CSA in methanol regenerated the diol system on the right side of the molecule (97 % yield), which was easily differentiated by reaction with TrCl´4-DMAP [19] [20] allowed the generation of aldehyde 80 (87 % yield), which reacted with the ylide generated from phosphonium salt Br À PPh 3 -(CH 2 ) 3 CO 2 Me [21] and KHMDS in THF to afford Z-olefin 81 (94 % yield). Exposure of 81 to LiOH cleaved the ester and acetate protecting groups, furnishing hydroxy acid 82 in high yield.…”