2-alkynoate ester 1-alkyne

Suitably protected amino acids (112) (cysteine, serine, and lysine) have been added via the side-chain heteroatom (S, O, and N, respectively) to conjugated alkynones, alkynoic ester and alkynoic amide (113). The expected heterosubstituted vinyl product (114) was formed in each case, mainly as the ii-isomer. In an accompanying paper, this type of addition was applied to the derivatives of fluorescein, 7-hydroxycoumarin, Sudan 1, and dansyl chloride with linker arms containing a conjugated terminal alkyne. 

Additives (cosolvents) which serve as ligands have great influence on the reducing power of Smlj. Allylic and propargylic derivatives are reduced via it-allylpalladium species, and the proton source has important effects on the generation of allenes or alkynes. Chiral allenic esters are obtained when pantolactone delivers a proton to racemic organosamarium species derived from 4-phosphato-2-alkynoic esters. ... 

The reactions of alkynes, alkynoic esters, ynamines, and dehydrobenzene with l,2-dithiole-3-thiones (2b), and occasionally l,2-dithiol-3-imines (12c), has been extensively studied <82AHC(3i)63>. The initial products for thiones are 3-thioacylmethylene-l,3-dithioles or thiazoles (111), which can react further to form di- or tri- adducts (113) and (114) respectively. Other rearrangements can give trithiapentalenes (6). Thials, formed from reactions of 5-unsubstituted-l,2-dithiole-3-thiones, can dimerize to products (112) with loss of sulfur (Scheme 14). Similar types of reactions have been observed with l,2-dithiole-3-thiones (2b) reacting with alkenes and ketenes, especially under... 

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