Photostimulated Reactions of Vinyl Phosphate Esters with Triorganostannides. Evidence for an SRN1 Vinylic Mechanism

• Published in: Journal of organic chemistry 2004-05, Vol.69 (11), p.3801-3805
• Main Authors: Chopa, Alicia B, Dorn, Viviana B, Badajoz, Mercedes A, Lockhart, María T
• Format: Article
• Language: English
• Subjects: Chemistry; Exact sciences and technology; General and physical chemistry; Kinetics and mechanisms; Organic chemistry; Photochemistry; Physical chemistry of induced reactions (with radiations, particles and ultrasonics); Reactivity and mechanisms
• ISSN: 0022-3263; 1520-6904
• DOI: 10.1021/jo049762t

Ketones are converted into vinyl diethyl phosphate esters (VinDEP), which under photostimulation reacted with sodium trimethylstannide (1) or sodium triphenylstannide (2) in liquid ammonia affording vinylstannanes via a vinylic SRN1 mechanism. Thus, (1-phenylvinyl)DEP (3), (3,4-dihydro-1-naphthyl)DEP (7), (3,4-dihydro-2-naphthyl)DEP (9), (E)-(1,2-diphenylvinyl)DEP (12), (E/Z)-(1-methyl-2-phenylvinyl)DEP (14) and (E)-(1-phenyl-2-methylvinyl)DEP (16) react with 1 and 2, under photostimulation, leading to the corresponding substitution products in good to excellent yields (45−89%). On the other hand, there is no reaction between (1-cyclohexenyl)DEP (5) or (1-benzylvinyl)DEP (18) with either 1 or 2, under similar conditions. These reactions appear to be strongly dependent on structural features of the vinyl phosphate since only conjugated vinyl phosphates afforded substitution products. These substitution reactions are completely regioselective and stereoconvergent. It seems to be the first example of a vinylic SRN1 process involving organotin anions as nucleophiles.