DEUTERIUM-LABELING STUDIES ON THE REGIOSELECTIVE AND STEREOSELECTIVE INTRAMOLECULAR HYDROSILATION OF ALLYL ALCOHOLS AND ALLYLAMINES CATALYZED BY PLATINUM AND RHODIUM COMPLEXES

Intramolecular hydrosilation of allyl alcohols and allylamines with the deuteriodimethylsilyl group(s) on the oxygen and nitrogen atom, respectively, has been studied under the catalysis of [Pt[{(CH2=CH)Me2Si}2O]2] or [{RhCl(CH2=CH2)2}2]. The silyl ethers examined include those of 3-hydroxy-1-alkenes (3) and their 2-methoxymethoxy (1), 2-methyl (2), and 1,1-dimethyl (4) analogues, and the silylamines are those of 3-amino-3-phenyl-1-propene (7) and the 2-methyl (5 and 6) and 1,1-dimethyl (8 and 9) analogues. Compound 1 forms five-membered cyclic products with Pt and Rh catalysts, which contain deuterium on C2 exclusively. In the five-membered cyclic products formed from 2, deuterium is distributed mainly on Cl and C2 and only slightly on the 2-methyl group. Compound 3 gives a five-membered ring product with Rh catalyst, in which deuterium is found on Cl and C2. Compound 4 forms a four-membered cyclic product selectively with Pt catalyst, which contains deuterium on Cl exclusively. With Rh catalyst, 4 (nondeuterated analogue) forms six-membered cyclic product selectively via olefin isomerization. The Pt-catalyzed reactions of allylamines 5-9 form four-membered cyclic products exclusively: while in the products from 5 and 6 deuterium is distributed on the two exocyclic methyl groups in comparable amounts, the products from 7-9 contain deuterium on Cl exclusively. With Rh catalyst, 5-7 form five-membered cyclic products, the deuterium distributions being similar to those observed in the allyl alcohol analogues: no reaction is observed with 8 and 9. These results are consistently analyzed mainly by the hydrometalation-reductive-elimination sequence and in terms of relative stability of the transition-metal-alkyl intermediates and the ring strain.