Hydrozirconation of Stannylacetylenes:  A Novel and Highly Efficient Synthesis of 1,1-Diiodo-, 1,1-Dibromo-, and Mixed (Z)- or (E)-1-Iodo-1-bromo-1-alkenes Using 1,1-Hetero-Bimetallic Reagents

Total Synthesis and Stereochemistry of the Antitumor Antibiotic PD 113,271

“…A Stille coupling reaction of the vinyl iodide 20 with the known stannane derivative 6 , followed by phosphorylation of the resulting alcohol, gave 21 (Scheme ). Deprotection of the allyl ester and deprotection of the silyl ether with in situ generated Et 3 N·2HF 18 in acetonitrile provided 1a as a sodium salt with a 92% yield in two steps.…”

One‐Pot Synthesis of Unsymmetrical 1,3‐Butadiyne Derivatives and their Application in the Synthesis of Unsymmetrical 2,5‐Diarylthiophenes

“…Rao et al circumvented this drawback by generating 1‐bromoacetylene in situ from the reaction of 1,1‐dibromo alkenes and terminal acetylenes, using the CuI/K 3 PO 4 /TBAA and DMF catalytic system at 90 °C in 4 h of reaction . However, the preparation of 1,1‐dibromo alkenes is problematic due to use of the air sensitive Schwartz's reagent, or because of the tedious and laborious extractions and purifications of phosphorus by‐products in the Wittig‐type protocol …”

“…[19] However, the preparation of 1,1-dibromo alkenes is problematic due to use of the air sensitive Schwartz's reagent, or because of the tedious and laborious extractions and purifications of phosphorus by-products in the Wittig-type protocol. [20] Recently, Li et al [21] developed an attractive alternative method for the synthesis of unsymmetrical 1,3-butadiynes, based on gold-catalyzed Cadiot-Chodkiewics-type cross-coupling, using terminal alkynes and alkynyl hypervalent iodine reagents. The main drawback is the difficulty of preparing hypervalent iodine.In another strategy, Fiandanese et al [22] employed 1,4-bis(trimethylsilyl)-1,3-bytadiyne as the starting material.…”

One-Pot Synthesis of 1-Iodoalkynes and Trisubstituted Alkenes from Benzylic and Allylic Bromides

“…By submitting p -tolyl bromide ( 2e ) to modified conditions with CHI 2 Cl, and by avoiding the inclusion of additional base, ( E ) - iodo-( Z )-chloroalkene 5 could be isolated with good yields and stereoselectivity. Currently, there are very few available methods for the stereoselective synthesis of such alkenes . The stereochemistry observed was confirmed by derivatization via a chemoselective Stille cross-coupling. , However, with CHI 3 and CHI 2 Br, the second elimination step from the corresponding alkene could not be avoided, and a significant amount of 1-iodoalkyne ( 1e ) was observed by crude 1 H NMR.…”

“…Currently, there are very few available methods for the stereoselective synthesis of such alkenes . The stereochemistry observed was confirmed by derivatization via a chemoselective Stille cross-coupling. , However, with CHI 3 and CHI 2 Br, the second elimination step from the corresponding alkene could not be avoided, and a significant amount of 1-iodoalkyne ( 1e ) was observed by crude 1 H NMR.…”