Synthesis of β-silyl ketones via reaction of trimethylsilyllthium with unsaturated hydrazones. Application to the synthesis of brevicomin

Investigating the Nature of Palladium Chain-Walking in the Enantioselective Redox-Relay Heck Reaction of Alkenyl Alcohols

“…The carboxylic acid, ( Z )-3-hexenoic acid, was prepared according to a previously reported procedure from ( Z )-hex-3-en-1-ol (3.0 g, 30 mmol), and its purity was confirmed by 1 H NMR. 16 The ester was prepared in the same manner as described for methyl ( Z )-oct-5-enoate and was purified using flash chromatography eluting with a gradient of 5–20% ethyl acetate to hexanes to give a clear oil in a 37% yield over two steps (1.1 g): R f = 0.72 (80:20 hexanes/ethyl acetate); 1 H NMR (CDCl 3 , 300 MHz) 5.62–5.46 (m, 2H), 3.68 (s, 3H), 3.09 (d, J = 6.3 Hz, 2H), 2.05 (p, J = 7.5 Hz, 2H), 0.97 (t, J = 7.5 Hz, 3H) ppm; 13 C{ 1 H} NMR (CDCl 3 , 125 MHz) δ = 172.6, 135.3, 120.3, 52.0, 32.9, 20.9, 14.1 ppm; IR (neat) 3025, 2964, 2876, 1738, 1436, 1402, 1330, 1305, 1255, 1162, 1114, 1070, 1018, 982, 933, 893, 870, 844, 692 cm –1 ; HRMS (ESI-TOF) m / z [M + Na] + calcd for C 9 H 13 O 2 Na 129.0916, found 129.0925.…”

Magnesium-induced regiospecific C-silylation of suitably substituted enoates and dienoates

“…These stabilizing effects play important roles in directing the regioselectivity in various organic reactions, especially in b-silyl carbonyl compounds. Some recent examples include BaeyereVilliger oxidation, 9 BamfordeStevens reaction, 10 Beckmann fragmentation, 11 Curtius reaction, 12 Norrish type I and II cleavages, 13 palladium-catalyzed nucleophilic substitution, 14 Nazarov cyclizations, 15 decarboxylation reactions, 16 stereospecific 1,2-silyl shifts, 17 and cyclobutane 18 formation.…”

α-Thioalkylation of Zinc Dienolates as an Entry to 4-Substituted 1-tert-Butoxy-7a-methylhexahydroindenes

“…[6b] Moreover, an undesirable O-alkylation cannot be avoided and mixtures of the C-and Oalkylated products are formed. [6a,c,e] Only the use of highly S  2 reactive [7] electrophiles like -bromoacetophenone affords the 4-substituted hexahydroinden-5-ones in reasonable yields. [8] In an extension of our previously reported method for the synthesis of 4-substituted hexahydroindene-5-ones 4 by thioalkylation of zinc dienolate 2, [9] we report here the synthesis of 4-substituted hexahydroinden-5-ols 6 and their corresponding hexahydroindene derivatives 10 by in situ reduction of the initially formed 4-substituted hexahydroindene-5-ones 4.…”