Selective alkylation of β-ketoester enolates using O-methyl aminosulfoxonium salts; the first example of C-alkylation using sulfoxonium salt electrophiles

Abstract

The alkylation of P-ketoester enolates with O-methyl aminosulfoxonium tetraphenylborate salts is reported; good t o excellent selectivity for C-vs. 0-alkylation is observed, and is found to be dependent o n the nature of the P-ketoester, solvent, metal counterion and aminosulfoxonium salt.

Tandem C- and O-alkylative annulation of β-ketosulfones with 1,2-bisbromomethyl arenes: one-pot construction of sulfonyl indanes and dioxadibenzofused macrocycles

“…After the equilibrium of E / Z isomerization was achieved, D1 could be converted into D2 , which had an E / E configuration. 9 Furthermore, 8a was formed via the double O -alkylation of D2 with another molecule of 10a . Meanwhile, 7a was produced via the K 2 CO 3 -mediated α-deprotonation of B and intramolecular C -alkylation of the resulting E1 intermediate.…”

Amides in One Pot from Carboxylic Acids and Amines via Sulfinylamides

“…5-fold. As we thought that the addition of 3A to the sulfinyl amide could be accelerated by increasing its electrophilicity, we explored the reaction of pyrrolidine p -nitro­benzene­sulfinyl amide with 3A . To our surprise no trace of carboxamide 4aA did form after prolonged heating to 70 °C, in the absence or in the presence of 1 equiv of DMAP.…”

1-Benzenesulfinyl Piperidine

“…Thus, treatment of the glucosamine donor 16 with BSP/Tf 2 O/TTBP at −60 • C in dichloromethane, followed by addition of 4,6-glucopyranosyl diol (17) furnished the trisaccharide 18 in 85% yield as a single isomer (eq 6). 18 (6) The generality of the BSP/Tf 2 O glycosylation method has been displayed in Crich's synthesis of the salmonella type E 1 -core trisaccharide (25), wherein the three glycosidic bonds were all prepared using this methodology. 4 Thus, reaction of the thiogalactoside (19) with BSP/Tf 2 O, in the absence of TTBP, with the alcohol 20 provided the thiorhamnoside (22) as a single isomer in 80% yield.…”

“…C-Alkylation of β β β-Ketoester Enolates. 6 Treatment of 1 with MeOTf in MeNO 2 , followed by anion exchange with sodium tetraphenylborate gave the sulfoxonium salt 32 (eq 10). Reaction of this sulfoxonium salt with the β-ketoester 33 provided a 3:1 mixture favoring the C-alkylated product 34 over the O-alkylated material 35 (eq 11 …”