Partial Reductive Demethylthiolation ofa-KetoketeneS,S-Acetals with Sodium Borohydride/Nickel Chloride: A New, General Method for 2-Methylthio-1-alkenyl Ketones

Synthesis of β-Amino-α,β-unsaturated Ketone Derivatives via Sequential Rhodium-Catalyzed Sulfur Ylide Formation/Rearrangement

“…Procedure for the Preparation of (E)-3-(Methylthio)-1-phenylprop-2-en-1-one 2j. 17 To a stirred suspension of nickel chloride hexahydrate (1.706 g, 7.2 mmol) in ethanol (10 mL) was added sodium borohydride (340 mg, 9.0 mmol), in small portions (15 min) and the mixture was further stirred for 10 min. A solution of ketene S,S-acetal 2a (650 mg, 2.7 mmol) in ethanol (5 mL) was added to the black suspension, and the mixture was further stirred at room temperature for 10 min.…”

[4 + 2] Cycloaromatization of 4-Bis(methylthio)-3-buten-2-one with Active Methylene Ketones: A Simple and Facile Phenol Annulation

“…A few of the annulated phenols ( 4d − f , h ) were desulfurized with Raney Ni (W2) to give the corresponding dethiomethylated products 5d − f , h in high yields. Alternatively, the synthesis of sulfur-free annulated phenols 5d , f , h could also be accomplished in good yields by cycloannulation of the respective ketones with β-methylthiomethyleneacetone 6 prepared by our earlier reported procedure through partial reductive dethiomethylation of 2 with nickel boride 1 1 β-Phenol Annulation of Various Ketones a Yields of Raney Ni desulfurization.…”