Treatment of terminal acetylenes (R1CCH) with secondary or tertiary alkyl iodides (R2I) in the presence of triethylborane provides the corresponding alkenyl iodides (R1C(I)CHR2) in good yields.
Iodine atom transfer addition reactions with alkynes. Part 1: Alkyl iodides
作者:Dennis P. Curran、Dooseop Kim
DOI:10.1016/s0040-4020(01)86550-9
日期:1991.8
Simple 2° - and 3° -alkyl iodides add smoothly to electron deficient alkynes under standard atom transfer conditions 10% Bu3SnSnBu3, sunlamp photolysis. Mechanistic experiments help to interpret stereochemical and yield trends, and a new model for atom abstraction reactions of rapidly inverting a-vinyl radicals is proposed.
Triethylborane Induced Stereoselective Radical Addition of R<sub>3</sub>SiH to Acetylenes and Stereoselective Reduction of Alkenyl Iodides with Tris(trimethylsilyl)silane
Triethylborane induced radical addition of various organosilanes (R3SiH) to acetylenes has been studied. Among them, tris(trimethylsilyl)silane (TTMSS) proved to be the best reagent for the hydrosilylation of acetylenic compounds in terms of yield and stereoselectivity. For instance, reaction of 1-dodecyne with TTMSS at room temperature for 3 h under Et3B catalyst provided (Z)-1-tris(trimethylsilyl)silyl-1-dodecene
An exceptionally stereoselective and general synthesis of (Z)-α-haloacrylates, ready to undergo various synthetic transformations, has been demonstrated from α-haloacetates and aldehydes in a one-pot manner via the titanium-enolate based asymmetric aldol condensation. Besides being an expedient synthetic procedure, the ready availability of diverse α-haloacetates, exceptional stereoselectivity, and high yields make the process a versatile transformation in organic synthesis. The potential of this method in up-scaling operations has been illustrated.