Synthesis, X-ray Diffraction Analysis, and Multinuclear NMR Study of (Z)-3,4,4-Trimethyl-1-(triphenylstannyl)-1-penten-3-ol and Its Monoiodinated Derivative

Abstract

The syntheses of (Z)-3,4,4-trimethyl-l-(triphenylstannyl)-l-pentene-3-ol ( 1) and (Z)-3,4,4trimethyl-l-(iododiphenylstannyl)-l-penten-3-ol (2) are reported. The solid-state structures of these tetra-and triorganotin compounds were determined by X-ray diffraction methods. The tin atom in 1 exists in a tetrahedral geometry distorted toward a trigonal bipyramidal one, with the distortion due to the close approach of the OH atom, i.e. 2.772(5) Á. A trigonal bipyramidal geometry is found in 2 where the oxygen atom, which forms significant 0-Sn interactions of 2.498(4) and 2.550(4) Á for the two independent molecules, respectively, is in an apical position as is the iodine atom. The different strengths of the HO-Sn interactions are related to the Lewis acidities of the respective tin centers. Crystals of 1 are triclinic, space group PI, with a = 11.120(6) k,b -11.652(6) k,c -9.998(5) Á, a = 110.15(5)°, ß -106.39(4)°, = 87.74(6)°, V = 1164(1) Á3, and Z = 2. Crystals of 2 are triclinic, space group PI, with a = 12.631(4) k,b = 13.887(1) k,c = 12.252(4) Á, a = 95.91(2)°, ß = 107.00(3)°, y = 74.67(2)°, V = 1981(1) Á3, and Z = 2. The structures were refined to final R -0.048 for 1 and R = 0.038 for 2. These compounds were characterized in solution by , 13C, and 119Sn NMR spectroscopy. The existence of an intramolecular HO-Sn coordination in solution was assessed by 13C and 119Sn secondary isotope multiplet of partially labeled entities (SIMPLE-NMR) experiments.

Syntheses, Structures, and Complexation Studies of Tris(organostannyl)methane Derivatives

“…These interactions cause, in part, a slight lengthening, as compared with the sum of the covalent radii of tin and iodine (2.73 Å), with the other Sn−I distances ranging from 2.7352(10) [Sn(3)–I(3)] to 2.7708(11) Å [Sn(1)–I(1)]. They fall in the range of the Sn−I distances for tetra‐ and [4+1]‐coordinated triorganotin iodides such as fc(SiMe 2 CH 2 ) 2 Sn(I)CH 2 CH(CH 2 OC 2 H 4 OCH 2 ) 2 (2.7309(4) Å), Ph 2 ISnCHCHCMe( t Bu)OH [2.7710(8), 2.763(1) Å], and Ph 2 ISnCH 2 CH 2 CO 2 Me [2.811(2) Å]. The position of the experimentally determined geometry for each tin atom along the path tetrahedron→trigonal bipyramid can be quantified by the geometrical goodness Δ∑( θ ) .…”

The O‐Directed Free Radical Hydrostannation of Propargyloxy Dialkyl Acetylenes with Ph3SnH/cat. Et3B. A Refutal of the Stannylvinyl Cation Mechanism

“…We were also cognizant of the generally good ( Z )‐selective O‐directed free radical hydrostannation outcomes that had previously been reported for propargylically‐oxygenated terminal acetylenes with triaryltin hydrides and 0.01 equiv. of benzoyl peroxide in Et 2 O at rt by the groups of Willem, Gielen, and Mu; and also by Dussault who used Ph 3 SnH and 0.01 equiv. of Et 3 B/O 2 as the initiator (Scheme ).…”

“… The O‐directed free radical hydrostannation of various terminal acetylenes with different Ar 3 SnH reagents in Et 2 O and C 6 H 6 under a variety of rt initiated conditions ,,,…”

“…Thus, when we began our work, no paper had yet been published that had provided a single clear‐cut example of the successful conversion of a vinyl‐SnPh 3 into a vinyl iodide. Instead, one or more of the phenyl groups was always selectively cleaved from the Ph 3 Sn moiety in such systems and a vinyl(aryl)tin halide was always typically formed instead (Scheme ) ,,. Likewise, in other sterically hindered vinyl triphenyltin substrates where the allylic‐OH was not internally coordinating, yet again, Ph−Sn cleavage occurred in preference to vinyl‐Sn cleavage, and once more vinyl iodide products were not formed (Scheme )…”

“… A summary of the early I−SnPh 3 exchange studies that had been carried out on tertiary ( Z )‐β‐triphenylstannyl allylic alcohols where a direct Sn−O interaction had been observed ,,…”