A new reaction of 1-bromoalk-1-ynes; synthesis of 3-alkylalk-1-ynes from terminal acetylenes

Total synthesis of aldehyde-containing Garcinia natural products isomorellin and gaudichaudione A

“…Over 30 years ago, an elegant proposal for the biosynthesis of isomorellin 8 was put forward by Quillinan and Scheinmann. 9 Unfortunately, they were hampered by the O-alkylation of 5,6-dihydroxy groups with bulky substituents. Till 2001 the first natural product with the caged structure, 1-O-methylforbesione, was synthesized by Nicolaou.…”

Polylithium compounds. 9. Sequential derivatizations of tetralithiopropyne, trilithio-1-butyne, and dilithio-3-methylbutyne with diethyl sulfate and trimethylchlorosilane

“…The relative rates of reaction for two simple anions with DeS and TMCS were also determined. The acetylide anion from 3,3-diethyl-l-pentyne (10) was prepared by hydrolysis of l5 and lithiation with n-butyllithium. Addition of this anion to a THF solution containing 5 equiv of both DeS and TMCS resulted in exclusive silylation to give 1.…”

“…The spectral characteristics for 1,1,3-tris(trimethylsilyl)-1,2pentadiene (16) were the following: 1H NMR (CC14) 1.87 (q, J = 7.2 Hz, 2 ), 1.02 (t, J = 7.2 Hz, 3 ), 0.04 (s, 18 ), 0.00 (s, 9 H); IR (neat) 2965, 2905, 1890, 1260, 920, 850 cm-1; mass spectrum m/e (rel intensity) 286 (10.5), 285 (21.6), 284 (M+, 66), 370 (9.5), 269 (3), 211 (9.6), 198 (10), 197 (24), 196 (100), 183 (3.8), 182 (9), 181 (40), 157 (3.2), 156 (5.6), 155 (29), 141 (9.4), 125 (2.4), 124 (2.4), 123 (14), 122 (40), 100 (1.4), 99 (11.4), 97 (9.2), 83 (8.2); exact mass, 284.1829 (caled for C,4H32Si3: 284.1812).…”

“…3,5-Bis(trimethylsilyl)-3,4-heptadiene(3). NMR (CC14) 1.85 (q, J = 7 Hz, 4 ), 0.96 (t, J = 7 Hz, 6 ), 0.03 (s, 18 H); l3C NMR (CeDe) ppm relative to Me4Si 205.4, 91.9, 22.5, 14.3, -1.1; IR (neat) 2960, 1900, 1850, 850 cm-1; mass spectrum m/e (rel intensity) 240 (14), 225 (5), 21 1 (13), 167 (31), 152 (23), 137 (10), 123 (7), 1 1 1…”

“…Journal of the American Chemical Society / 98:26 / December 22,1976 (17), 99 (10), 73 (100); exact mass, 240.1728 (caled for Ci3H2sSi2: 240.1729).…”