Alkynyltins Stille coupling

Alkynyltin compounds also take part in Stille coupling reactions with alkyl, aryl, or acyl halides or triflates (e.g., Equation (89)).251 These reactions are covered in Volume 11. 

Z)-Tributylstannyl 3-iodoacrylates undergo Stille couplings with alkynyltin reagents to form (Z)-2-en 4-ynoic acid intermediates 642, which cyclize to yield either 5-methylenefuran-2(5//)-ones 643 or 2//-pyran-2-ones 644 (Scheme 149, Table 30). Factors that affect whether the pyranone or furanone cyclization predominates from this... 

Table 30 Products of the Stille coupling of (Z)-tributylstannyl 3-iodo-acrylates and alkynyltin reagents (Scheme 149)...

I 9 Cross-Coupling Reactions to sp Carbon Atoms Table 9.17 Examples of the Stille alkynyltin cross-couplings with organotriflates. 

AUcynylstannanes can cross-couple with a variety of other functional groups employing the Stille protocol. Couphng to acyl chlorides is a well-known procedure that affords aUcynylketones in respectable yields. Other reports include alkynyltin cross-couplings with a-haloethers and a-halocarbonyls, enol phosphinates and phosphonates, alkenyl(phenyl)iodonium salts, alkynyl halides, and allyl hahdes (Table 9.18). Alkynylstannanes have also been shown to cross-couple with iron halides under the Stille conditions to effectively form iron-carbon bonds. 

Table 9.16 Selection of recent Stille cross-couplings between organohalides and alkynyltin reagents.

Scheme 9.28 The Stille cross-coupling of alkynyltin 82 with the iodoarene 83 using the iminophosphine-ligated Pd catalyst 81 [247].

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