Syntheses and crystal structures of two di-naph-tho[2,1- d:1',2'- f][1,3]dithiepine atropisomers

Abstract

The closely related title compounds, 1-(di-naphtho-[2,1-d:1',2'-f][1,3]dithiepin-4-yl)-2,2-di-methyl-propan-1-ol, C₂₆H₂₄OS₂, 1 and 2-(di-naphtho-[2,1-d:1',2'-f][1,3]dithiepin-4-yl)-3,3-di-methyl-butan-2-ol, C₂₇H₂₆OS₂, 2, both comprise an atrop-isomeric binaphthyl di-thio-acetal unit substituted at the methyl-ene carbon atom with a chiral neopentyl alcohol grouping. The overall stereochemistry of the racemate in each case is defined as aS,R and aR,S. In 1, the hydroxyl group generates inversion dimers via pairwise inter-molecular O-H⋯S hydrogen bonds whereas in 2, the O-H⋯S link is intra-molecular. Weak C-H⋯π inter-actions link the mol-ecules into extended arrays in both structures.

Keywords: C—H⋯π contacts; asymmetric synthesis; atropisomer; bi­naphthalene di­thiol; crystal structure; hydrogen bonds.

Figure 1

The mol­ecular structure of 1 with displacement ellipsoids drawn at the 50% probability level.

Figure 2

The mol­ecular structure of 2 with displacement ellipsoids drawn at the 50% probability level.

Figure 3

The mol­ecular structures of 1 (left) and 2 (right) aligned with the C101—C201 bond on the z-axis. The intra­molecular C—H⋯S bond of 2 is shown as a red dotted line.

Figure 4

Inversion dimers of 1 formed by pairwise O—H⋯S hydrogen bonds (red dotted lines).

Figure 5

Chains of 1 in the a-axis direction formed by C—H⋯π inter­actions (blue dotted lines) and supported with C—H⋯S close contacts (red dotted lines); Cg3 is the C201–C204/C210/C209 ring centroid.

Figure 6

Twofold screw of 2 in the b-axis direction formed by C—H⋯π inter­actions (blue dotted lines); Cg2 is the C105–C110 ring centroid.

Figure 7

Glide reflection of 2 in the bc plane formed by C—H⋯π inter­actions (blue dotted lines); Cg4 is the C205–C210 ring centroid.

Figure 8

Preparation of 1 and 2.