ISSN:
0009-2940
Keywords:
cis;-2-Boryl-1-stannylalkenes
;
Addition reactions
;
Exchange reactions
;
Solvent-controlled reactions
;
Tin - Element bonds
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Behaviour of cis;-2-Boryl-1-stannylalkenes Against (Dimethylamino)trimethylstannane, Methoxytrimethylstannane, and Methanol - Formation of New Tin - Element Bonds, Examples of Solvent-Controlled ReactionsWhen alkene derivatives1 [Me3Sn(R1)C=C(R)BR2], with the trimethylstannyl- and the dialkylboryl group in cis position at the C=C double bond, are treated with (dimethylamino)-trimethylstannane (4), methoxytrimethylstannane (5), or methanol, the product distribution depends remarkably on the solvent [hexane or tetrahydrofuran (THF)]. In hexane, 1a, b (R1=H, R=Et, Pr) react with 4 to give the B-dimethylamino compounds 6a, b in high yields as a result of addition and rearrangement. Other derivatives 1 do not react with 4 in hexane. Under the same conditions in hexane some alkenes 1 react with 5 to yield the B-methoxy derivatives 8, which are analogous to 6. A complex mixture of various products is obtained from the reaction of 1 with methanol in hexane. If the same reactions are carried out in THF, many compounds 1 react with 4 and 5 to eliminate tetramethyltin and give dihydro- 1,2,5-azonia- (7) or dihydro-1,2,5-oxoniastannaboratoles (9), respectively. The reaction with methanol in THF also leads to the oxonia-stannaboratoles 9, this time by elimination of methane. Pure samples of compound 9g are obtained as the crystalline THF adduct 9g-THF. A mechanism is proposed involving adduct formation at the boryl group, followed by intramolecular reactions depending on the donor quality of the respective solvent.
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19911240314
